TDAC Timing: When to Submit Your Thailand Arrival Card

People ask this one earlier than any other TDAC question, usually right after booking flights: how far ahead can I actually do this thing? The honest answer disappoints planners. You can't get it out of the way a month early, or even a week early. The window is short, it's tied to when you land rather than when you leave, and missing that detail is the single most common reason people end up filing in a panic at the departure gate.

The 72-hour rule, without the fine print

The Thailand Digital Arrival Card is issued within 72 hours, three days, before you arrive in Thailand. Not three days before you fly out. Not three days before your trip starts if you've got a layover in Seoul or Doha first. Three days before the moment your plane, bus, or boat actually reaches Thai soil.

That distinction trips up more travelers than anything else on this form. Someone flying Chicago to Bangkok with a long connection might leave home on a Tuesday and not touch down until Thursday. The clock for their TDAC starts counting from Thursday, the arrival, not Tuesday, the departure. The card is issued inside that final three-day stretch and not before, so working from your departure date puts you ahead of a window that hasn't opened.

Working it out for your own flight

The math is simple once you separate "when I leave" from "when I land." Take your scheduled arrival time in Thailand, count back 72 hours, and that's the earliest moment you can file. Everything after that point, right up until you're standing in the immigration line, is fair game.

If you land in Thailand...	Your filing window opens...
Monday, 10:00 AM	Friday, 10:00 AM
Wednesday, 3:00 PM	Sunday, 3:00 PM
Friday, 7:00 PM	Tuesday, 7:00 PM
Sunday, 8:00 AM	Thursday, 8:00 AM

Notice the window always opens on the same clock time, three days earlier, whatever day of the week that lands on. A Friday arrival doesn't get a longer runway than a Tuesday one. We tell customers to treat the window opening as a reminder trigger, not a deadline to race toward. There's no reward for filing at the earliest possible minute, and no penalty for filing an hour before you land, aside from your own stress levels.

Land and sea crossings count from the border, not the border town

Everything above assumes a flight, but the requirement isn't an airline rule. It's been mandatory for every non-Thai national entering by air, land, or sea since May 1, 2025, when it replaced the old paper arrival card. The timing works identically for a land crossing: the 72-hour window counts back from the moment you actually cross into Thailand, not from when you leave your hotel in Vientiane or Phnom Penh, and not from when you book your bus ticket.

The practical wrinkle is connectivity. An airport departure lounge has reliable WiFi; a queue at a land border post often doesn't. If you're crossing overland, fill the form the evening before at your hotel rather than gambling on a signal once you're standing at the crossing itself.

One entry, one card, one arrival date

Here's the part the timing question usually hides: the card you receive isn't a general pass for your trip. The Immigration Bureau prints it as valid for one time use only, for travel on the specific arrival date you gave. That single sentence is why "when should I submit" and "will my card still work" are really the same question.

If your flight shifts by a few hours, that's not a problem. The arrival date and flight number are both fields you can update after submission; the only locked fields are your name, passport number, nationality, and date of birth. But if your plans change in a bigger way, say you fly in, spend a week in Laos, and come back through a land border before your flight home, that return leg needs its own TDAC. The card you filed for your first arrival was already used up the moment you crossed in. Border runs and multi-entry trips are the scenario where "I already did this" gets people in trouble; each crossing into Thailand starts its own 72-hour clock and needs its own filing.

Who gets to skip this entirely

Not everyone needs to think about timing at all. If you're connecting through a Thai airport and staying in the transit area the whole time, without ever passing through immigration control, you're exempt. No card, no window to track, nothing to file. The instant you clear immigration for any reason, even for one night at an airport hotel before an early connection, that exemption disappears and you're back to the same 72-hour rule as everyone else.

Families, groups, and the baby who's never left the house

Timing gets slightly more coordination-heavy with a group, not because the rule changes but because everyone's clock has to line up. One submission covers up to 10 travelers arriving together, so a family doesn't file four separate forms with four separate windows to remember; it's one sitting, timed to the shared arrival. Every traveler still needs their own card, infants included. There's no age where the requirement quietly stops applying, and parents are sometimes surprised that a six-month-old needs one just as much as they do.

If you've genuinely forgotten until the last minute

This happens more than you'd think, and it's rarely fatal. Because the window only opens 72 hours out, a lot of "I forgot" moments aren't actually too late, they're just later than ideal. If you're at the departure gate with a phone and a signal, you can still file; the form doesn't care that you're cutting it close, only that you're inside the window. What matters more at that point is the inbox you use. The Immigration Bureau delivers the submission details and QR code to your email only, so pick an address you can actually open with airport WiFi, and check your spam folder the moment you land if it hasn't shown up.

Why we built a service around a 72-hour window

Timing is, honestly, the whole pitch. We've filed 1,749 TDACs on the official system since June 2025, and the pattern we see most is people who understood the rule perfectly well and still missed it, because travel days are chaotic and a three-day countdown is easy to lose track of between packing, connections, and time zones. What we sell is watching that clock so you don't have to. Send us your travel details and we submit inside the correct window, every traveler, one arrival date at a time.

If you'd rather see exactly what's on the form before deciding whether to hand it off, the field-by-field walkthrough covers every section. Traveling with kids adds its own small wrinkles, covered in the guide for families.