There's no masjid in Hua Hin but there are 3 in Cha Am, which is about 20 minutes from Hua Hin. One of them which is the easiest to access is Masjid Nurul Ehsan. Coming from Bangkok, you have to make a U-turn after seeing a huge Fly Now Outlet on your right. Drive past the PTT petrol station and turn into the first left turn with a big arch. Drive for about 3 km, crossing the railway tract till you see the following giant photo frame of the King and turn right. Continue driving till you see the masjid on your left.
Now that you know where the masjid is, you will not miss performing your Friday prayer while holidaying in Hua Hin or Cha Am ;)
There's a little Muslim food stall behind the masjid.
I had kuayteow nuea (beef soup noodles) while Khun K had plain rice with stir fried beef with basil leaves and omelette.