If you clear Immigration you will need a ThailandPass.

They understand that flights can be changed frequently at the moment. They won't worry about an insignificant deviation like this from your visa, and as Stuart says you can arrive up to 72 hours after the scheduled time without any change to your ThailandPass. Just remember to update your hotel/transfer/test and make sure your preflight PCR result is still within 72 hours of your departure.

They'll be knocking on your door with cuffs the minute the clock ticks past midnight.

@Sarah ********

Contact them and explain the predicament. They can contact the hotel and speak to them in Thai.

@Sarah ********

Did you book through Agoda or Booking<dot>com?

@Stan ******

No worries.

@Stan ******

Where is Bangla in Bangkok? Did you mean BangNa?

Did you think about asking the hotel at all?

@Stan ******

Stan do you think since the original post was about Patong that he might mean Bangla Road?

@Stan ******

That's all it is.