Upvote:0
Well, it doesn't answer my question but it's quite close; there are vans going out of Ekammai bus terminal in 05:00,
quite close to 03:00 but not the same effect of course:
Upvote:2
Most buses to Hua Hin leave not from Ekkamai, but from the New Southern Bus Terminal (Sai Tai Mai). However, Sai Tai Mai is in far western Bangkok a solid 10 km from the city center and not reachable by BTS/MRT, so you're likely to run into traffic jams just trying to get there...
I know you said "bus only", but I would still recommend the train. Trains to Hua Hin depart from Hualamphong (Bangkok's main station) roughly hourly, you can take a daytime train without fear of jams, and Hualamphong is easily reached by MRT.