Does onward travel have to be a flight?

No, not everywhere. Thailand, which is one of the countries most associated with the requirement, explicitly accepts non-flight transport in its own visa-exemption wording, and United States regulations drop the round-trip ticket requirement entirely for Visa Waiver travellers arriving at a land border.

The complication is that “does it have to be a flight” has two audiences hiding inside it. An immigration officer is assessing whether you have a credible plan to leave. An airline check-in agent is deciding whether to put you on an aircraft. Those are different people applying different standards, and a bus ticket can satisfy the first while leaving you stuck at the second.

This article sets out the wording we can actually source, the places where the answer is genuinely unpublished, and what to carry if your exit is by land or sea.

The clearest official wording anyone has published

Thailand’s visa-exemption text is unusually specific. The Royal Thai Embassy states that foreigners entering Thailand “by any means” under the Visa Exemption scheme are required “at the port of entry” to have proof of planned travel — “(confirmed air, train, bus, or boat tickets)” — to leave Thailand within the exemption period.

Two things follow from that single sentence, and both are worth stating plainly.

• Thailand explicitly accepts non-flight transport. Train, bus, and boat are named in the official text alongside air. This is not an inference or a traveller anecdote.
• Thailand’s rule is an immigration condition, applied at the port of entry, to people arriving “by any means”. The widespread claim that Thailand’s onward-travel requirement is “just an airline rule” is wrong, and it is wrong in the direction that gets people turned around at the border rather than at the departure gate.

Two checks, two decision-makers

The reason a straight answer is hard is that your document has to pass up to two different people, and only one of them is applying the country’s published rule.

The immigration officer at arrival applies the entry condition. If the rule says “proof of planned travel to leave the country”, a confirmed ferry booking or a land-crossing bus ticket is exactly the kind of thing that rule contemplates, and in Thailand it is named outright.

The check-in agent at your departure airport is doing something else. Airlines carry the cost and the penalty of returning anyone refused entry, so check-in staff apply a conservative screen of their own. What that screen accepts is not published by any government. The industry data product airlines consult, IATA Timatic, is a paid B2B service with no public interface, so no one outside the industry can verify what it says for a given route on a given day. Treat “the airline will accept a bus ticket” and “the airline will refuse a bus ticket” as equally unverified claims. The one documented exception is New Zealand, which names the check-in desk in its own official text.

The practical consequence: the further your exit plan sits from a normal airline booking, the more useful it is to have the rest of your file with you — funds, accommodation, visa status, and a clear account of the route.

The United States writes the distinction into its regulations

The clearest illustration that “onward travel” is not synonymous with “flight” is in US law. Visa Waiver Program travellers arriving by air are subject to a statutory round-trip transportation ticket requirement, and 8 CFR 217.2(a) defines that ticket broadly enough to include an electronic ticket record rather than a paper coupon.

Arriving at a land border, the same programme drops the requirement outright. 8 CFR 217.2(c)(2) states that a round-trip transportation ticket is not required for Visa Waiver applicants arriving at a land border. What they show instead is evidence of financial solvency and a domicile abroad which they do not intend to abandon.

One warning, because it is the single most common error in articles on this topic: none of this applies to people holding a B-1 or B-2 visitor visa. The round-trip ticket rule sits in the Visa Waiver Program regulations and has no visa-holder equivalent. For a visa holder, a return ticket is evidence toward the ties-abroad test, never a condition of admission. Do not carry the Visa Waiver rule across.

Where the rule exists but the mode is not specified

Most countries that require onward proof do not say which mode counts. Indonesia’s Directorate General of Immigration asks visa-on-arrival, e-VOA and visa-free arrivals alike for “a return ticket or onward ticket to continue the journey to another country” — a requirement stated across every visitor category, with the mode left open. Costa Rica’s official entry information asks for a return ticket or proof of onward travel to another country, alongside a visa-free stay of 180 days, not the 90 that circulates in travel articles.

When the wording is open like this, a genuine, confirmed land or sea booking is a reasonable reading of the rule. It is still a reading. Say to yourself honestly that you are relying on an officer’s interpretation rather than on published text, and prepare accordingly.

Where no rule is published at all

For some countries there is simply nothing to cite. Mexico is the clearest example: the US State Department’s unusually detailed entry section for Mexico never mentions a return or onward ticket, and the relevant article of the Ley de Migración could not be retrieved from any official route. That means Mexico is not evidenced either way — not required, and not proven not-required.

Brazil is a different shape of answer. Decreto 9.199/2017 Article 170 uses the permissive verb “poderão ser exigidos” — such documents may be required. That is a documented discretionary power of the federal police, not an obligation on the traveller. Brazil should never be described as “requiring” onward proof.

The rule to take from this: absence of a published requirement is not a guarantee of entry. If nobody can point you to the text, nobody can tell you a bus ticket will be accepted either. What they can tell you is that entry is discretionary and that a thin file makes a discretionary decision harder.

Thailand’s day count is changing — do not trust a number in an article

A Cabinet decision of 19 May 2026 approved revoking the 60-day visa-exemption scheme and reducing the list of countries eligible for the 30-day scheme. It takes effect 15 days after publication in the Royal Gazette, and at the time of writing the Gazette date is not confirmed.

So the requirement itself is stable — you need proof of planned travel out of Thailand within the exemption period — but the length of that period is actively moving. Any article that states a fixed day count for Thailand, including one written this week, may be describing a scheme that no longer exists by the time you read it. Check the current figure on the Thai government’s own e-Visa portal before you book the exit.

If your exit is by land or sea, carry this

• The booking itself, confirmed rather than a search result, with your name on it, and a date inside your permitted stay.
• A one-page written itinerary showing how the trip fits together, so the officer can see the exit without reconstructing it from three screenshots.
• The published wording for the country you are entering, saved offline. In Thailand’s case, the sentence naming train, bus, and boat is worth having on your phone.
• Funds evidence and accommodation details, because both the US land-border carve-out and Singapore’s advisory wording tie onward travel to solvency rather than treating the ticket as a standalone test.
• A realistic plan B if the check-in desk is the sticking point rather than the border — usually a cheap refundable fare or a genuine airline hold you can produce on the spot.

The short version

Thailand says in writing that a train, bus, or boat ticket counts, and applies the rule at the border rather than leaving it to airlines. The United States removes the ticket requirement entirely for Visa Waiver arrivals at a land border. Those two facts are enough to retire the idea that onward travel must always mean a flight.

Everywhere else, the answer depends on wording that is often vague and sometimes absent, and on a second decision-maker at the check-in desk whose standards no government publishes. Make the exit plan real, make it readable on one page, and check the country’s own text rather than trusting a number in an article — including this one.