I want to check into a hotel in Singapore at 3 am. On what day should I reserve a room?

After three o'clock in the morning, it should be the next day (that is, the 28th).

In short, I checked in in Shenyang in the early morning and checked out at 3 noon the next day.

This is what I know, and I have lived like this. As for Singapore, I don't know if this is the case.

I hope I can help you.

have a nice trip