No overstay in the OP' case :)
2 separate dates:
Visa expiration date: [15 May 2017] the date in which the visa expires. So to use that specific visa, you must enter on or before the expiration date listed on the visa.
Permission to Stay date: [17 May 2017] The date in which the entrant must physically exit the country via border immigration checkpoint (or extended at a local immigration office). Usually the permission to stay stamp will have both the entry date and the exit by date stamped or printed in the passport and/or on some type of arrival/departure slip affixed to the passport.
Permission to stay is what counts after you enter any country....
OP must leave Thailand
23:59:59 on 17 May 2017 to avoid overstay charges. Most land borders close before that time....local immigration offices typically work 08:00-17:00; don't wait until the last second :D
1) The easiest way to remember this is that you usually acquire a visa BEFORE entering a country. The permission to stay is acquired when you are stamped in by border immigration OR
extended in-country at designated gov't [immigration] office.
2) If you hear cases where someone is doing a so-called
border run or
visa run, it is usually because they either:
- have a multiple entry (ME) visa,
- entering under the Visa Exempt scheme, or
- are acquiring a new visa from a [nearby] Thai Embassy/Consulate.
In either case, technically they are exiting the country (Thailand) >> entering and exiting a different country >> entering the desired country (Thailand) again. When it is all done on the same day, it is casually known as an
Out-In entry. (You go out and come back in the same day)
3) Bonus: Some Thai international airport border may waive overstay fine if you are only overstay < 24 hours. I would not recommend relying on that though.