Porting your mortgage when you move home in South Wales
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Quick answer: Porting means taking your existing mortgage deal — the rate and terms — with you to the home you're buying, instead of paying an early repayment charge to leave it. Two things surprise people: it's the deal that moves, not the loan, so you go through a full new application with the same lender; and if the new home needs a bigger mortgage, the extra is a second product at today's rates, not more of your old one. Porting usually wins while you're inside a fixed period with an ERC — and often doesn't once the fix has ended.
What porting is
Most fixed-rate and tracker mortgages sold in the UK are "portable", a word that makes the process sound simpler than it is. What moves to the new home is your deal: the interest rate, the time left on your fixed period, and the terms that came with it. The lender's decision to lend does not move automatically.
Porting is a new mortgage application to your current lender, for the new home, based on your circumstances now. The lender values the new home and checks your income and spending again under its current rules. It can say no, even though it already lends to you. If it says yes, your old deal carries on at the new address. No early repayment charge (ERC: the fee for leaving a deal early) is due on the amount you port.
When porting beats a new mortgage, and when it doesn't
It usually comes down to two questions: is there an ERC to avoid, and is your current rate better than today's rates?
Scroll sideways to see every column.
| Situation | Usually better | Why |
|---|---|---|
| Inside a fixed period, ERC applies, your rate is below today's | Port | Keeps the cheap rate and avoids an ERC of typically 1–5% of the balance |
| Inside a fix, but today's rates are lower than yours | Run both numbers | Paying the ERC to take a cheaper new deal can win — only the arithmetic on your actual figures settles it |
| Fix has ended (or ends around your moving date) | New mortgage | Nothing to port that's worth keeping — you're free to look at other lenders |
| Your lender declines the port | New mortgage | A different lender may read your circumstances differently — a decline from one is not a decline from all |
The same habit from our remortgaging in South Wales guide applies here: compare the total cost of each realistic option (monthly payment × months, plus fees and any ERC), not just the headline rates.
Moving up: the top-up
A typical South Wales move, from a flat or terrace to a semi, usually needs a bigger mortgage. That's where a ported mortgage ends up in two parts:
- Your ported balance stays on the old rate and old end date.
- The extra borrowing goes on a separate deal from the same lender's current range, at today's rates, with its own fixed period.
This has two effects. First, your overall monthly cost sits between the two rates, so a cheap ported part doesn't make the whole loan cheap. Second, the two parts usually end on different dates, which can leave one part free to switch while the other still has an ERC. Where you can, pick a top-up deal that ends on, or close to, the ported deal's end date. It makes it much easier to remortgage (switch the whole loan to a new deal) in one go later.
Moving down, or porting less
You might port only part of your balance, which is common when downsizing or when a good sale price cuts the mortgage you need. If so, you'll usually pay the ERC on the part you pay off, though not on the amount you port. Some lenders waive or refund the ERC if you complete the new purchase within a set time of paying off the old loan. Time limits and conditions vary by lender, so check the porting wording in your mortgage offer rather than assuming.
The affordability catch
Ports fail most often not on the property but on the new checks on you. Anything that's changed since your original mortgage is assessed afresh. That includes a move into self-employment or contracting, a new job where you're still on probation, parental leave, credit issues since, or simply stricter rules at the lender. Passing the original application years ago counts for nothing.
If your lender says no, treat that as one answer, not the final word. Lenders can reach quite different decisions on the same facts (that's the idea behind our affordability check). A port turned down by one lender often goes through as a new mortgage with another, with the ERC included in the comparison.
Timing: a port moves at the speed of your chain
A port completes when your sale and purchase do. So it shares every timing risk of your chain (the linked sales and purchases that depend on each other):
- Most lenders expect your sale and purchase to complete together or close together. A long gap between selling and buying can mean paying off the loan now and reapplying later, with an ERC in between.
- A mortgage offer (ported or not) typically lasts around six months. A new-build home with a far-off completion date can outlast it.
- Selling a leasehold flat in Cardiff Bay or the city centre? Leasehold means you own it for a set number of years, but not the land it stands on. The leasehold paperwork adds time on the selling side of the chain, not just the buying side.
The Welsh costs of the move itself
Porting saves the ERC. It doesn't change the costs of moving:
- Land Transaction Tax (LTT), the Welsh version of stamp duty, is due on the purchase. At main rates there's nothing to pay on the first £225,000 and 6% on the part from £225,001 to £400,000, with higher rates above that. The average Cardiff home, at £273,095 (May 2026, UK House Price Index), means a bill of roughly £2,900. Get your exact figure from the stamp duty Wales calculator.
- Higher LTT rates apply if you complete the purchase while you still own your previous home. The second-homes and buy-to-let LTT guide explains the extra charge and the rules on getting it refunded when you sell later.
- Valuation, legal work on both the sale and the purchase, and moving costs are the same whether you port or not.
FAQ
Can I port my mortgage to a more expensive house?
Usually, if the new affordability check supports the total borrowing. Your current balance moves on its old rate and the extra goes on a second deal at today's rates, all with your current lender.
Do I have to reapply to port my mortgage?
Yes. A port is a full application with your current lender, with a new valuation and fresh checks on you. Portability only secures the deal itself, and only once the lender approves the new lending.
Can my lender refuse to port my mortgage?
Yes. Portability means the deal can move; it doesn't oblige the lender to approve the new loan. A change in income, new credit issues or stricter rules can all stop it. A refusal from your own lender doesn't end the move. It changes the comparison to "a new mortgage elsewhere, minus the ERC".
Do I pay an early repayment charge if I port?
Not on the amount you port. You can still pay one if you port only part of the balance (it's typically charged on the part you pay off), or if the loan has to be paid off between your sale and purchase. Some lenders refund the ERC if you buy again within a set time, so check the porting section of your offer.
Does porting work if I'm moving elsewhere in South Wales, or further afield?
Yes. The deal can move anywhere in the UK the lender will lend, subject to the same checks, and the new property still has to pass its valuation and rules. A move to Newport or anywhere else in South Wales ports exactly as a move across Cardiff does.
Where to go next
If your fix has ended, or a full switch looks worth it, the remortgaging in South Wales guide covers the other side of this decision, including ERC sums and timelines. For the move itself, the salary needed in South Wales guide sets the price context, using Cardiff prices. The affordability check estimates, lender by lender, what your income could support: ported, topped up or new.
Prefer to check your affordability first? Check how much you could borrow →
