What is the best visa option for UK retirees planning to stay in Thailand for an extended period?

The longest is an OA visa applied for in the uk is valid for 1year, as it's multi entry you can leave to a neighbouring country & return before the expiry date & will be stamped in for another 12 months assuming you have insurance for the length of your stay. With this method you get very nearly 2yrs & can keep your money in the uk if you want to.

The other option is a Multi Entry Tourist Visa which is valid for 6months for a 60day stay whuch can be extended by a further 30days once in Thailand after which you would need to leave & return. This would give you upto 270 days if timed right.

It is also possible to arrive visa exempt for 30days which can be extended by another 30. Again you can leave, reenter & repeat but only officially allowed 2 per year & I'd reccomend leaving for at least a few days inbetween.

Which is best for you depends on the funds you have availble & how long you want to come for. For a permanent move I'd reccomend either an O visa or METV then set up the bank requirements & do an extension based on retirement once you're here

Non Imm OA. It's a 1year multiple-entry visa.

if short time (Under 1 year) purchase the 6 month METV visa for $200 or pounds i guess in the UK prior to your trip and with a strategic border bounce just days before it expires you can get 9 months out of this visa...each arrival stamp will be for 60 days which you can extend for 30 days at your local immigration office for 1,900THB to get 90 days at a time in country....

or..

you can purchase the 60 day SETV visa for $40 or pounds which with an extension for 30 days at a cost of 1,900THB at your local immigration office gives you 90 days in country

Seeing that you over 50 you can also get a retirement visa

Good luck

Retirement