Originally Posted by dsgtc0408

Just to be clear, I assume you have *A gold status in OnePass (per your heading)?

As info, the SATS lounge (SATS Premier lounge) that UA uses in SIN has showers, hot food, drinks (regular and booze), a fair selection of reading material. There's also four massage chairs in the far back, and two online terminals (there's wifi if you want to use your own notebook). I don't think the SATS lounge is open all night but should be open when the UA check in counter opens for the HKG and NRT flights in the morning (check in counter definitely open by 5:30 AM). Unfortunately UA customers do not have access to the SQ SilverKris lounge.

There are other lounges but you would need some sort of status to access them - I'll leave that to other posters to respond to, also the question of whether or not any of the lounges are open all night.