When should I apply for a 60-day visa for Thailand while in Singapore?

If you are in Singapore and plan to return to Thailand on the 20th, you should apply for your 60-day visa as soon as possible. You can apply online, and once your application is approved, you will need to drop off your passport and necessary documents. The approval process is quick; you can typically submit your application in the morning and collect your passport the next afternoon. Remember that the visa validity begins upon entry into Thailand, and you will have 3 months from the approval date to enter and activate the visa.