Originally posted on: 24 November 2025
Updated on: 16 February 2026
1. Introduction
So, you’ve made the move. You’ve swapped beach weekends for brisk walks through Hyde Park, learnt which Tube line to avoid at rush hour, and you’re finally pronouncing “Gloucester” the British way. Life in the UK is starting to feel normal, though a cold Christmas still feels a bit off.
Meanwhile, your Australian assets, your shares, an investment property, maybe a managed fund you set up years ago, have just been sitting quietly in the background. At some point, you’ll probably want to tidy things up: cash out those investments, sell down a portfolio, or bring money across to the UK for a house deposit.
Most Aussies assume this part will be straightforward.
“I’ll pay tax in Australia and that’ll be it, right?”
“There’s a Double Tax Agreement, so I won’t get taxed twice… surely?”
In reality, things are rarely that simple.
The moment you become a UK tax resident, HMRC becomes extremely interested in every capital gain you make, whether it happened in Melbourne, Brisbane, or the Sunshine Coast. And because the Australian and UK tax systems don’t line up on cost bases, currencies, timing, or even the concept of “deemed disposals”, you can find yourself facing a tax outcome you would never have predicted back home.
This article breaks down exactly how the UK taxes your Australian shares, property, and investments, why so many expats get caught off guard, and what you should consider before you sell anything. It’s written specifically for Aussies living in the UK (or thinking of moving), so you can understand the rules clearly and avoid paying a penny more tax than you legally have to.
Here is the next section, written in your established No Worries Accounting tone, UK English spelling, and keeping everything clear, calm, and accessible.
2. The First Big Trap: Australia’s Exit Tax vs the UK’s “Original Cost” Rule
For Australian tax purposes, leaving the country can trigger what is known as a deemed disposal. In simple terms, the ATO pretends you sold all your CGT assets that are not “taxable Australian property” on the day you stopped being an Australian tax resident. In practice, this often includes things like shares, managed funds, and crypto. Your Australian real property, such as your former home or an investment property, usually stays within the Australian tax net and is not treated as sold on departure.
At that point, you are given two choices.
Choice A: Pay the exit CGT straight away
The ATO calculates the gain up to the day you left, and you pay the tax in that year. For Australian purposes the cost base resets to market value on the day you departed, meaning any future growth on that asset is ignored by Australia. This is why many Australians believe the “slate is wiped clean”.
Choice B: Defer the exit tax
If you choose to defer, the ATO keeps those assets within its tax system by treating them as if they were taxable Australian property. When you eventually sell them, Australia taxes the entire gain from the original purchase date, not just the part that happened after departure.
Both choices can be sensible in the right situation, but they have very different consequences once you become a UK tax resident.
2.1 What the UK Does When You Arrive
The UK’s approach is more straightforward but far less forgiving.
The UK does not recognise Australia’s deemed disposal, nor does it accept the cost base reset that follows if you paid the exit tax. HMRC simply looks at what you originally paid for the asset and what you eventually sold it for, and will tax the full gain over that period.
- There is no cost base uplift when you arrive in the UK.
- There is no alignment with Australia’s deemed disposal.
- There is no automatic reset that wipes out pre-departure growth.
From a UK perspective, the asset has one lifetime, one cost base, and one eventual gain, regardless of what the ATO treated as a taxable event years earlier.
2.2 Why This Creates Double-Tax Exposure
This is where things get tricky, because the two systems do not talk to each other.
If you paid the exit tax in Australia, you might expect the UK to give you credit for that tax when you eventually sell the asset while living in the UK. Unfortunately, that often isn’t how it works.
Foreign tax credit relief in the UK only applies when:
- the foreign tax relates to the same gain, and
- it is charged in the same tax year as the UK gain.
Australia’s exit tax fails both tests. It was paid years earlier, and it was charged on a “sale” that never really happened. When you then sell the asset for real, HMRC treats the earlier Australian tax as irrelevant to the UK calculation. The result is that the same slice of growth can end up taxed twice.
If you deferred the exit tax, the picture improves slightly. Both countries tax the same real-world sale in the same year, so the UK credits usually work as intended. If Australia charges more tax, the UK tax is wiped out. If the UK charges more, you pay the difference to HMRC.
The key point is that two tax systems are running in parallel, each with its own rules about when a gain happens and how it should be measured. If you do not plan ahead, the clash between them can produce a tax bill you weren’t expecting.
3. The Currency Conversion Sting
Even if the timing of the Australian and UK tax charges lines up perfectly, there is another layer that can catch people out: foreign exchange. The UK does not work in Australian dollars. HMRC wants everything in pounds, and that simple fact can turn a modest gain in AUD into a sizeable taxable profit in GBP. It can also work the other way and quietly reduce, or even eliminate, a gain.
3.1 How the UK Looks at Foreign Currency Assets
For UK capital gains tax purposes, you cannot simply calculate your profit in AUD and then convert the final number to sterling.
Instead, HMRC expects you to:
- convert the original purchase cost into GBP using the exchange rate on the date you bought the asset, and
- convert the sale proceeds into GBP using the exchange rate on the date you sell.
Only then do you work out the gain or loss. The foreign exchange movement over the holding period is therefore built directly into your UK gain.
3.2 When FX Makes the Gain Look Bigger
Consider a simple example.
- You bought shares in 2005 for AUD 50,000 when £1 was worth AUD2.55.
- UK cost: £19,600.
- You sell in 2025 for AUD 52,500 when £1 is worth AUD 2.
- UK proceeds: £26,250.
In Australian dollar terms, you have only made a AUD 2,500 gain over 20 years, which does not feel particularly dramatic.
In sterling terms, the UK sees a gain of £6,650. That full £6,650 is potentially taxable, even though the underlying investment barely moved in AUD. The “profit” has come largely from the pound weakening against the Australian dollar. From HMRC’s point of view, that does not matter. It is still a chargeable gain.
3.3 When FX Works in Your Favour
The currency story is not always bad news, and over the past 15 years it has generally shifted in favour of the UK based Australian.
- If the pound strengthens between the time you bought and sold, the gain in GBP terms can be much smaller than the gain in AUD.
- In some cases, a small AUD profit can shrink to a negligible gain in sterling, or even flip into a loss.
For example, if the numbers above were reversed and the pound had strengthened, your AUD gain might turn into a very modest GBP gain. That would reduce, or possibly eliminate, your UK CGT exposure, even though you pay a perfectly normal capital gains amount in Australia.
So FX can exaggerate the gain or quietly soften it. You only find out which way it goes when you run the calculation in pounds.
3.4 What You Should Do Before You Sell
Before you sell any Australian investment as a UK resident, it is worth doing a quick FX sense check.
- Work out the original cost in GBP using the historic exchange rate at purchase.
- Convert a realistic expected sale price into GBP at today’s rate.
- Compare the GBP gain with the AUD gain you might be expecting from the Australian side.
If the UK gain is much larger because of currency movements, you may decide to rethink the timing of the sale, or at least go in with your eyes open. If the FX shift works in your favour, it is still important to document the calculation properly so that your UK return is accurate and you can show your working if needed.
Either way, the message is simple: never assume the UK tax position will mirror the Australian numbers. The exchange rate story can completely change the outcome.
4. The Main Residence “Disaster”: Selling Your Aussie Home From the UK
For many Aussies, the biggest asset tied up back home is not a share portfolio, it is the family home. On paper this feels safe, because both Australia and the UK have long had capital gains exemptions for a main residence. The problem is that Australia changed the rules for expats, and the UK did not match that change. The result is a nasty gap between the two systems.
4.1 How Australia Now Treats Your Former Home
Up until a few years ago, it was fairly common for Australians living overseas to sell their former home while abroad and still claim the main residence exemption. That door was closed several years ago.
From 30 June 2020, if you are a non-resident for tax purposes at the time you sign the contract to sell your former Australian home, you generally lose the main residence exemption completely. It does not matter that you lived in the property for years before moving overseas, or that it was unquestionably your home for most of the ownership period.
There is a very narrow “life events” exception that can preserve the exemption in specific circumstances, for example certain situations involving death or terminal illness, and even then there are tight time limits on how long you can have been non-resident. Most ordinary expats will not qualify.
In practice, this means:
- Australia treats the sale as fully taxable, from the original purchase price through to the sale price.
- You are taxed as a foreign resident, so:
- there is no tax free threshold,
- non-resident rates apply from the first dollar, and
- you do not get the 50 per cent CGT discount for the period after 8 May 2012.
On top of that, there are withholding rules. For higher value properties, a percentage of the sale price is withheld at settlement and sent straight to the ATO as a credit against your eventual tax bill. This does not change the total tax you pay, but it is a very real hit to your cash flow on completion.
4.2 How the UK Looks at the Same Sale
The UK is more generous on main residence relief, even for a home in another country.
If the Australian property genuinely was your main residence for part of the time you owned it, the UK will usually give Private Residence Relief for that period. The gain is time apportioned. Broadly speaking:
- the years you actually lived in the property as your home are exempt,
- the final nine months of ownership are also treated as exempt, even if you had already moved out, and
- only the remaining period is exposed to UK CGT.
So if you owned the house for 15 years, lived in it for 10, then rented it out for 5 years while in the UK, the UK will tax roughly one third of the total gain.
However, because you are now a UK tax resident, you still have to declare the sale on your UK return, even though the property is in Australia. The gain is calculated in pounds, and normal UK CGT rates for residential property apply.
4.3 How the Two Systems Interact in Practice
This is where the double tax agreement steps in.
- Australia, as the country where the property is located, has the primary right to tax gains on that property.
- The UK, as your country of residence, can also tax you on the gain.
- To prevent true double taxation, the UK gives you a foreign tax credit for the Australian CGT you have paid on the same gain.
In real life, this means you usually end up paying whichever country’s effective tax rate on that gain is higher.
The real sting for many expats is that Australia now ignores the fact the property used to be your home, while the UK still respects that history. Australia taxes the full gain, the UK only a slice, but the presence of that large Australian bill means you rarely see much, if any, UK tax on top.
4.4 Why Timing Matters
If you are thinking of selling an Australian home while living in the UK, timing can make a very big difference.
- Selling while you are a non-resident of Australia usually means no main residence exemption and a large Australian CGT bill.
- Selling at a time when you have re-established Australian tax residency may, in some cases, restore access to the exemption, although that comes with its own residency complications.
Every situation is different, and trying to coordinate residency, property markets, and personal plans is not always realistic. The key is not to assume the old “sell the family home while overseas and pay no tax” stories still apply.
5. Changing Rules for New UK Arrivals: From Remittance Basis to FIG
If you have been in the UK a while, you may already have heard of the “remittance basis”. If you are only just arriving, you are more likely to hear about something new called the FIG regime. Both are ways of softening the UK tax hit on foreign income and gains for people who are not long-term UK residents. The important point is that the old system has been phased out and a new, shorter window of relief is now in its place.
This matters a lot if you are an Aussie with sizeable investments back home and you are planning when to sell. We have covered this in previous posts, so let’s just hit the highlights below.
5.1 The Old World: The Remittance Basis
Under the old rules (up to April 2025), many non-UK domiciled individuals can choose to be taxed on the remittance basis. In simple terms, that means:
- UK tax is charged on UK income and gains as they arise,
- foreign income and gains are only taxed if you bring the money into the UK,
- anything left offshore can sit there without an immediate UK tax charge.
This was attractive for long-term expats with investments abroad, but it came with some catches:
- you lose your UK personal allowance and CGT annual exemption in years you claim it,
- once you have been resident for 7 out of 9 years you may have to pay an annual remittance basis charge, and
- after 15 years you are treated as “deemed domiciled” and cannot use the regime at all.
In other words, it was helpful, but gradually became more expensive and eventually disappeared altogether.
5.2 The New World: The FIG Regime from April 2025
From 6 April 2025, the remittance basis was abolished and replaced with the Foreign Income and Gains (FIG) regime. The idea is simpler. Rather than focusing on domicile, the UK looks at how long you have been resident.
If you have not been UK tax resident in any of the previous ten tax years, then for your first four years of UK residence you can claim FIG. During those FIG years:
- foreign income and foreign capital gains are not taxed in the UK at all,
- you can bring the funds into the UK without triggering UK tax,
- you are only taxed in the UK on UK source income and gains.
For an Aussie arriving fresh into the UK, this creates a clear four-year window where you can, in principle, sell Australian assets without a UK capital gains tax bill, as long as you claim FIG correctly. Australia may still tax the sale, but the UK steps back for that period.
Used well, the FIG regime can make a very meaningful difference to your overall tax bill on Australian investments. Used badly, or ignored entirely, you can drift out of the four-year window and find that a sale which could have been free of UK tax is now fully exposed.
In the next section, we will bring everything together and look at practical steps you should take before selling, so you can see both the Australian and UK angles clearly before you commit.
“…the service has been fabulous.”
Ah Mike, we think you’re pretty fabulous too!
6. Before You Sell Anything: Your Essential Preparation Checklist
By this point it is probably clear that selling Australian assets while you are living in the UK is not something to do on a whim. The good news is that a bit of planning, and some numbers up front, can make a big difference.
Here is a practical checklist to work through before you press sell.
6.1 Confirm Your Tax Residency in Both Countries
Everything starts with residency. You need to know, for the year of sale:
- Are you UK tax resident under the Statutory Residence Test?
- Are you still treated as an Australian tax resident, or have you clearly become non-resident under Australian rules?
- If there is any doubt, how would the UK Australia tax treaty resolve a dual residency situation?
The treaty has tie breaker rules that decide which country gets to treat you as resident if both try to claim you. That can affect who taxes the gain, and how credits are given.
Getting residency wrong is a fast way to get the whole calculation wrong.
6.2 Run the Numbers in Pounds, Not Just in Dollars
Next, work out the UK position properly in sterling, not just in AUD.
For each asset you are thinking of selling:
- find the original purchase price and the date you bought it,
- find the expected or actual sale proceeds and the date of sale,
- convert each figure into GBP using the rate on that specific date,
- then calculate the gain or loss in pounds.
This is the only method HMRC will accept. You cannot do an Australian dollar gain and convert the result at today’s rate.
6.3 Check What You Did About Australia’s Exit Tax
If you left Australia owning shares, managed funds, or other non-TAP assets, you should confirm exactly what happened at the time you became non-resident:
- Did you accept the deemed disposal and pay exit CGT, with a cost base reset for Australian purposes?
- Or did you elect to defer the exit tax, so that Australia will tax the whole gain on a future real sale?
This choice drives how the two systems now interact.
- If you paid the exit tax, keep records of the calculation and the tax paid, even if it is difficult to use as a credit later.
- If you deferred, be ready for Australia and the UK to tax the same sale in the same year, but with foreign tax credit relief normally working as intended.
If there is any suggestion the treaty might restrict Australia’s taxing rights on a particular asset, it is worth getting specialist advice.
6.4 Map Out Any FIG Window You Have
If you have arrived, or will arrive, in the FIG era, check whether you qualify for the four-year Foreign Income and Gains exemption and, if so, exactly which tax years it covers.
Ask yourself:
- Could some of your planned disposals fall within those four FIG years, so that the UK does not tax the gain at all?
- Would selling just before or just after you become UK resident produce a better overall answer?
- Are you happy to give up your personal allowance and CGT annual exemption for any year in which you claim FIG?
FIG does not change what Australia does, but it might spare you a second layer of tax in the UK if you time things carefully.
Here is a polished sales-style closing section that mirrors the tone, structure, and warmth of your Kiwi/UK example, but tailored to Aussies and this specific capital gains topic. It flows naturally from the wrap-up you already have.
7. How We Can Help
You do not need to become an expert in UK / Australia tax law to get this right. What you do need is a clear sense of how the two systems interact and how your real life story fits into the rules. A bit of early planning around residency, the exit tax, your timing, and the FX picture can completely change the outcome.
At No Worries Accounting, we spend a lot of time talking to Aussies who are either planning the move to the UK, have recently arrived, or are now looking at selling assets they left behind. We understand exactly how the ATO and HMRC line up, where they clash, and how to navigate the grey areas in between.
If you are thinking of selling your Australian shares, managed funds, or property while living in the UK, or you are simply unsure how your residency or exit tax position affects your plans, feel free to get in touch for a quick chat. A brief conversation up front can clear up the uncertainty and often prevent an unnecessary tax hit.