Compared across countries

Where can you smoke?

For a trip that crosses borders — the same question, answered country by country.

The pattern

Four of the five ban indoor smoking nationally. The United States does not — it leaves the rule to each state, and as of mid-2024 that meant bars were smokefree in 29 of them and restaurants in 35. Among the four, the e-cigarette is where they diverge: China names it inside the indoor ban, and Taiwan goes further and makes importing one illegal.

United States

There is no national answer — this is left to the states, and they disagree. As of mid-2024 the CDC counted bars smokefree in 29 states and restaurants in 35, so the honest rule is to assume indoors is out and look for the sign.
Japan

It is the reverse of what most visitors expect: indoors is generally banned, and so is smoking while walking outdoors. You look for a designated area.
China

Indoors is banned outright in the big cities, e-cigarettes included, and the rules are written city by city rather than nationally.
South Korea

Every restaurant, bar and café is no-smoking regardless of size, and a lot of outdoor space is too. Fines run to 100,000 won.
Taiwan

Indoors is banned by national law, with one narrow exception for a properly sealed smoking room. The part that catches visitors is the vape: an e-cigarette is not merely restricted here, it is illegal to import, sell or use — and using one carries the same fine as smoking where you must not, NT$2,000 to 10,000.

Sort the practical stuff before you fly.