North of the Similans lie Ko Bon, Ko Tachai, the Surin Islands, and Richelieu Rock. All of these areas offer world-class diving that differs from the Similans and should be part of your itinerary when you visit the area.

Ko Bon: The Perforated Island

Ko Bon is located about 20 kilometers North of island #9 and features one of the only vertical walls in Thailand. The dive site is on the Southwestern point and consists of a 33 meter wall facing the small cove, and a step-down ridge that carries on to depths of over 45 meters. Leopard sharks are common on the ridge and on the sandy flats below the wall. Although the soft corals are not as high-profile as they are in the Similans, the colors of the corals are radically different and include shades of turquoise, yellow and blue, besides the more common pinks and purples. Ko Bon is one of the better places to see manta rays, especially towards the end of the season when there is more plankton in the water.

Ko Tachai

Twenty-five kilometers North of Ko Bon, Ko Tachai has an offshore underwater ridge that runs perpendicular to the island. This is considered to be one of the finest dives in the Kingdom and is famous as a place to see not only the more common species of corals, fans and tropical fish, but larger animals such as rays, leopard sharks, nurse sharks and hawks bill turtles. Whale sharks make an appearance on a regular basis. Tachai also boasts a breathtaking sandy beach on its Northeastern shore; a great place to hang out and feel like Robinson Crusoe.

Surin & Richelieu Rock

The Surin Islands, although visited by several dive operators from Phuket, are more appropriately famous for their beautiful coves, bays and dense jungle than they are for their diving. Spending a few idyllic days on a sail boat or other yacht here are the stuff dreams of paradise are made of yet the serious diver will be bored easily after a few dives because of the generally poor visibility and lack of fish.

Surin's ace card, however, is a small submerged rock about 18 kilometers East of Surin. Richelieu Rock, just exposed at the lowest of tides-thus a navigational hazard for those boats not equipped with a GPS navigation system-rates as one of the best places in the world for swimming with our gentle giant, the whale shark. Encounters with these fish-the largest of all fish-are rare almost any place in the world. But for some reason, Richelieu attracts more than its fair share. Swimming with such a large animal, known to grow to lengths of 20 meters or more, has to be a high point for any diver. Sightings occur 50-70 percent of the time, depending on the time of year. Generally, February, March and April are the best times for a visit. The big difference between diving here and other areas that are famous for whale sharks, such as Western Australia, is that we don't need spotter planes as the sharks cruise around the rock, and the visibility is normally excellent. Who knows why they are here, but the sharks aren't around because of plankton blooms like in Australia. Thus, clear water.

During the past couple of the years we have seen a decline in the number of whale sharks for some odd reason. It may be due to the effects of the El Niņo weather effects or it could be some other reason. We are still keeping our fingers crossed that they will return in the numbers we have come to expect.

The good news, however, is that we have been seeing more sharks and manta rays than we've seen in years. So, though you may not see whale sharks as often as you would have a few years ago, the big animal diving is still good.