Koh Samui aims to implement quarantine-free travel for inoculated visitors from Oct 1 in tandem with Phuket.
"Koh Samui wants to grab tourist demand as there are many destinations globally that require no quarantine," said Ratchaporn Poolsawadee, president of the Tourism Association of Koh Samui.
Koh Samui is expected to be the first area in Surat Thani to test entry procedures for foreigners because the island has an airport.
Koh Phangan and Koh Tao are reachable via ferry transit and they can develop their own entry standards.
Mr Ratchaporn said Koh Samui's district chief officer insisted local communities have no opposition to a quarantine-free tourism plan.
The island also joined the tourism sandbox, a pilot programme to accelerate the reopening process before the whole country opens up to the international market in the fourth quarter.
However, some 300,000 vaccine doses have to be administered in Samui to create herd immunity first, he said.
In addition, the government has to allow international commercial flights to transit in Bangkok at a sealed terminal before flying to Koh Samui.
Mr Ratchaporn said the aircraft type can be the 70-seat ATR 72-600, with one flight per week to facilitate the flow of tourists to the island without undergoing quarantine in Bangkok.
The association already arranged meetings with the Tourism and Sports Ministry and the Centre for Covid-19 Situation Administration for further discussion on the reopening scheme.
Meanwhile, to boost the domestic market, operators on three islands are hosting a promotional event called "Wonder Islands Samui, Phangan, Tao" from March 11-17 in Bangkok. They expect to stimulate the local economy via package sales worth a combined 20 million baht, with more than 5,000 hotel bookings.
Mr Ratchaporn said this event and the Songkran holiday should increase trips to the island and boost average occupancy to 60-70% in April from only 10% currently.
Tourism fairs are scheduled in other regions such as Chiang Mai and the Northeast to beef up inter-regional travel.
"The government should consider offering a 50% subsidy for ferry transit to every island destination," said Worapong Wongsuwan, vice-president of the Koh Tao Tourism Association.
He said a round-trip ferry package from Chumphon or Koh Samui to Koh Tao costs around 1,300 baht, and this subsidy would make it more likely Thais holiday on the islands.