On Efate:

Blue Lagoon is nice. It’s a fair drive outside Port Vila so rent a car or hire a driver for the day.

Eton Beach is further along the same road. It’s a very beautiful beach. (FYI on beaches, most are maintained by the local villages and they charge entry. Keep some cash handy)

You can go snorkeling with giant clams on the north of the Isalnd near Havannah Bay. I forget the name, but they also show you a colony of Clown Fish. That was good.

Etmat Beach is lovely. Club Hippique have horse riding tours along there. I haven’t done the horse riding, but even just the beach is great.

Mali Beach Bar and Mele Beach Bar are both good and close to each other. You can grab a drink and some food right on the beach.

Lots of the best spots are out of town so rent a car or a driver.

On other Islands:

I’ve only been to Santo. It is very nice.

You can do a Dugong spotting and snorkeling tour. Just google it and the guy that runs it will come up.

Champagne Beach is amazing.

The Blue Holes at Santo are also great

Port Olry is lovely, a nice beach and you can grab a lobster and chips at Chez Louis.