1

"Since I have already been to really good snorkeling locations around the world I am unfortunately quite demanding."

Then Vietnam and Cambodia will be disappointing. Laos even more so as it doesn't have a coast.

2

Quote" Since I have already been to really good snorkeling locations around the world I am unfortunately quite demanding."
Many areas are fishing sites as well eg. Nha Trang and dynamiting is one of the preferred methods of fishing which tends to scare away fish and blow up coral reefs. By the sounds of it you would be disappointed with places like that.Once I went on a "snokeling tour" in Nha Trang and saw two little silver fish. i was lucky...it must have been a good day!
Con Dao Islands (177kms from Vung Tao) has a large turtle nesting area and a dugong population around the shores.The area is basically protected as a National Park and is clean and has beautiful corals and zillions of fish.It's a long way to swim there but they have ferries and accomadation on the islands.

3

Phu Quoc Island for sure. Personnally, you should ask local TA to have safe trip.

Cheers,

4

Where is the best place for snorkeling in Vietnam, Laos and Cambodia?

Thailand!

Forget about Laos..... I concur with Phu Quoc Island.. if you don't mind the garbage....

5

I wouldn't bother.

6

btw VN air has small planes flying to Con Dao from HCMC. Apparently the island has a lot of history going back to the 1700s. I've never been but have spoken to people who have been and they love it!

7

with a snorkeling mask you can join village boys spearfishing in the streams & rivers of Laos

8

Friend, looks like not many folks are excited about snorkeling in Vietnam. Maybe you could contact some of the dive companies in Vietnam and see what they reccomend.