Your first 90 days in Thailand: what to do, in order

Nothing about settling in Thailand is difficult. The reason it takes people three months and a lot of frustration is that the steps have a required order, and almost nobody is told what it is.

Each document depends on the one before it. Do them out of sequence and you will stand at a counter being told no, for a reason nobody mentioned when you started.

The chain

This is the whole thing, and it only runs one way:

Thai SIM → lease → TM30 → certificate of residence → bank account

The bank needs the certificate of residence, because Thai anti-money-laundering rules require them to verify your address and a foreign passport does not carry one. Immigration issues the certificate against your lease and the TM30 filing. The TM30 is filed by your landlord, against the lease. And nearly everything needs a Thai phone number, because that is where one-time passcodes go.

Miss any link and the chain stops at that point. The common version: arriving at the bank in week two, being asked for a certificate of residence, discovering it needs a TM30 the landlord never filed, which needs a lease naming an owner whose documents you were never given.

The realistic timeline

Four to six weeks to a working bank account. Around 90 days to genuinely settled. The constraint is not effort — it is that these steps cannot be run in parallel, and each takes days rather than hours.

The two mistakes that cost the most

Signing a long lease in week one. From a hotel room, in a neighbourhood chosen from a map, before you have experienced the commute, the noise at 11pm, or the building’s internet on a weekday evening. Take a flexible month first. It costs a little more and saves a year of regret — Bangkok neighbourhoods ranked for founders is where to start.

Signing a lease whose paperwork does not support the chain. A lease not in your own name, or signed by an agent for an unnamed owner, or without copies of the owner’s house registration book and ID. It looks fine. It blocks the certificate of residence two months later, when you have already paid three months and moved in. The lease and deposit guide covers exactly what to collect at signing.

What is not urgent

Worth saying, because new arrivals often worry about the wrong things.

Thai tax. There is nothing to file on arrival. Thai tax residency is a pure count of 180 days of physical presence in the calendar year under Section 41 — nothing you do in your first 90 days changes it, and if you arrive late in the year you may not reach the threshold at all. See the 180-day rule.

The 90-day report. It only applies after 90 consecutive days inside Thailand, and the counter resets on any departure. If you leave for a weekend at day 80, nothing is due. Details in 90-day reports and TM30.

A Thai company. Almost certainly not needed. The DTV is designed for foreign-source income and requires no company or work permit — when founders actually need one.

What is urgent, and quietly so

Health cover with no gap. Your home-country entitlement often ends at deregistration rather than at your flight, and nothing announces it. Confirm the exact date the old cover ended and that the new cover started before it — health insurance in Thailand.

The evidence, from day one. This is the thing nobody does and everybody later wishes they had. Photograph every entry and exit stamp on the day it is issued. Keep the lease, the TM30 receipt, the 90-day slips, the bank account opening documents.

Thai tax residency is a day count. So, in practice, is the question your former tax authority will ask if it ever examines whether you really left. These records answer both, and they are records you did not create yourself — which is exactly what makes them credible. Ten seconds at the airport now, versus reconstructing a year of movement from a replaced passport three years later.

Account separation, if you have not already done it. Ideally this happened before you left. If it did not, do it before you cross the 180-day threshold: capital accumulated before Thai tax residency in one place, current income in another. See sending money to Thailand.

After 90 days

Once the chain is complete, the work becomes maintenance: a 90-day report each quarter if you stay put, a fresh TM30 each time you return from abroad, and the day count accumulating quietly towards whatever the year’s total turns out to be.

That is the point at which the destination side is done, and the only remaining question is whether the departure side was documented as well as the arrival side.

To model the numbers, run the Thailand tax calculator. For what it all costs, the Bangkok prices guide.

If you would rather have this sequence run for you — the lease read before you sign it, the TM30 chased, the bank appointment booked at a branch that processes DTV files — book the free diagnosis call. Landing support is the part of the engagement that happens after the paperwork.