Retiring abroad and the frozen pension rule
Your State Pension is payable anywhere in the world — but whether it rises each April depends entirely on where you live. In some countries it is triple-locked exactly as at home; in others, including Australia and Canada, it is frozen at the rate you first received abroad, forever.

The rule in one paragraph
The government's policy is that annual State Pension increases are paid abroad only where there is a legal requirement to uprate the pension. In practice that means: if you live in the European Economic Area (EEA), Switzerland, Gibraltar, or a country with a social security agreement with the UK that covers uprating, your pension rises each April just as if you had stayed in Britain. Everywhere else, your pension is frozen at the rate in force when you first became entitled abroad (or when you left the UK, if you were already claiming) — and it never rises again, even though it is still paid in full every week.

Which countries get the increase
Beyond the EEA and Switzerland, the uprating countries on the government's current list include Barbados, Bermuda, Bosnia-Herzegovina, Gibraltar, Guernsey, the Isle of Man, Israel, Jamaica, Jersey, Kosovo, Mauritius, Montenegro, North Macedonia, the Philippines, Serbia, Turkey, and the United States. The list changes from time to time as agreements change, so check the current GOV.UK list before making a long-term decision — do not rely on a blog post or a forum thread. Note the traps: the UK has social security agreements with Canada and New Zealand, but those agreements do not cover uprating, so pensions there are frozen. The same applies to Australia, South Africa, India, and most of Asia, Africa, the Caribbean, and Latin America.
What freezing costs over a retirement
Freezing sounds minor until it compounds. A pension frozen at £241.30 a week while UK pensions rise by even 2.5% a year falls behind by roughly £6 a week in year one, £12 in year two, and so on — over a 20-year retirement the gap runs into tens of thousands of pounds. That is why the destination decision matters more than almost any other retirement choice for a British pensioner, and why it should be made before the move, not after. One consolation: if you later move back to the UK, or to a country where uprating applies, your pension is increased to the current rate from that point. The frozen years are not backdated, but the freeze ends.
Claiming from abroad, and two warnings
If you have already moved abroad, you cannot use the standard UK online claim service. Claim through the International Pension Centre, which handles overseas claims and will also forward your details to state pension schemes in countries where you lived or worked. Keep DWP updated with your overseas address: it normally writes four months before your State Pension age, but only if it knows where you are. Two warnings: first, Pension Credit is not payable if you move abroad permanently, so do not count on it in a move. Second, time spent working abroad can still count toward your qualifying years in some cases (EEA, Switzerland, and agreement countries), but the amount you are paid is based only on your UK qualifying years — foreign years help you reach the 10-year minimum, they do not raise the weekly amount.

Official links
Frequently asked questions
I live in Spain. Does my pension rise each year?
Yes. Spain is in the EEA, so your State Pension is uprated each April exactly as if you lived in the UK.
I live in Australia. Is my pension really frozen forever?
Yes, unless you move to the UK or to an uprating country. Australia has no uprating agreement with the UK, so a pension first paid there stays at that rate.
If I move back to the UK, does my pension unfreeze?
Yes — from the move, your pension is paid at the current rate. The years it was frozen are not backdated or compensated.