Class 1 - IRC Racing 1

Keelboats with IRC 1.100 and above

Class 2 - IRC Racing 2

Keelboats with IRC 1.000 to 1.099

Class 3 - IRC Racing 3

Keelboats with IRC of less than 1.000

Class 4 - IRC Cruising

Keelboats with an IRC certificate but cruising in nature

Class 5 - IRC Charter Boat

Keelboats that are regularly chartered and compete under formal charter agreements

Class 6 - Sports Boats

Keelboats with an RORC Sport Boat handicap

Class 7 -  Platu

Platu Class Keelboats (Coronation Cup)

Class 8 - Ocean Multihulls

Ocean going Catamarans and Trimarans

Class 9 - Hobie Tiger

Class 10 - Hobie 16'

Class 11 - Open Monohull Dinghy

Beach launched monohulls

Class 12 - Laser

Class 14 - Optimist

Thailand Nationals