Tonsai, Krabi, Thailand is a climbing mecca and has beautiful and unique climbing. The overhanging limestone cliffs remind me of an outdoor cave without mud. Here is some beta if you are planning to go there I hope makes your trip easier for planning.
1-Get the f*** out of Bangkok - nothing worth seeing there for the pita for getting around
2-If you buy cheap flights, make sure you have enough baggage allowance. Paying for excess luggage for VietJet Air can cost you more than the ticket
3-Tonsai is accessed by water - plan for that
4-You take a boat to get to Tonsai
5-Plan to be dropped off in the water
6-Don't wear shoes, like for most of the trip
7-The crowd might be at Railay if you are not visiting in climbing season
8-High tide can make it tricky to get to Railay
9-Not a lot of boats come to Tonsai (at least in offseason)
10-Boats are $3 per person... if it is full and you are going to Railay. Otherwise it's $18 to rent the entire boat.
11-Lodging is cheap for a reason
12-Most of the climbing is more advanced since most cliffs are overhanging
13-Electricity is not running 24hrs in some parts
14-Base Camp is not near the beach anymore
15-Be prepared for the heat
16-Carefully swimming, there are jelly fish
17-Climbing spots and moving between towns is tide dependent
18-Mosquitos are pretty bad, use Permethrin and Deet
19-Don't drink the water or sketchy food or you get Tonsai Tummy
20-Popular season is December-February
21-Drink Water
22-Look up in the trees if you want to see monkeys