We've been to Krabi a few times and usually fly with those low cost airline. Normally fly with Air Asia. We don't need much for an hour journey. It's pretty cheap and many flights a day. You can fly to Krabi from Bangkok or from Kuala lumper (Air Asia) or from Singapore (Tiger Airways).
From Krabi Airport, we normally take airport taxi to Ao Nang. The cost is 600B fixed. The journey is 30K, around 20 min drive.
The Ao Nang Princess is the main ferry from Ao Nang to Phi Phi Don. The busiest being the 9.00 leaving from Nopparat Thara Pier. The Princess holds just under 200 passengers, has seating inside but on a nice day generally out sitting on the deck in the sun. There are toilet facilities on board and someone comes round selling drinks.
The journey to Phi Phi Don took about 2 hours with a stop in Rai Leh to pick up more passengers. On the way back we took up our spots on the upper level just under the 'driver' but as soon as we left the small bays and hit open water we wished we had sat inside. The sea was quite rough and the wind had picked up and whenever the boat hit a wave we were hit with cold water. There were quite a few green faces when we got back to Ao Nang. A horrible journey back, so my advice would be to sit inside when travelling late afternoon as the sea and wind are generally stronger at that time, especially if you're like me and don't have very good sea legs...
We booked the return journey at our hotel and cost us 800 bahts each. This seemed quite a lot so it will probably be cheaper to buy at the pier. Timetable in the link below.
If you need any help in arruival at Krabi bus station, go across the road to IX.TOURS, ask for Pieter (Dutch national). who will be glad to assist you. Pieter has settled down in Krabi and knows the region like hiss pocket.
a taxi to aonang is 600 baht from Airport, shuttle is 200 Baht per person.
We were told that our hotel will be the first stop by the sales lady, and the shuttle is leaving at that time, so we decided to follow the Shuttle.
However, we waited for nearly 30mins for the shuttle to get full. and we ended up the last one to get down from the Shuttle, and the worst thing is, the driver didn't know where our hotel was. he dropped us off somewhere about 3 mins walk to the hotel.
but later we found out that if the shuttle would have take the othter way, we will be the first to be dropped off
Boats to Ko Phi Phi Island leave from the main pier at 10:00 and 15:00, cost 350B one way, which includes transport from Krabi Town to the pier about 3km away. I booked my return ticket from a travel agency place in the hotel I stayed out (The Grand Tower Hotel) where the price was 700B. The trip takes about 1.5hrs and you can sit outside in the sun with your legs dangling over the side.
It's possible to get a bus/ferry combo ticket to Krabi from Ko Samui. I booked mine through a travel agents in central Chaweng on Ko Samui which cost 500 baht. I got picked up early in the morning from my hotel and we picked more people up and headed towards the ferry pier in Nathon. We then transferred onto an oldish looking bus that then took us south to another pier outside Nathon where we got on to the ferry bound for Dousak. The ferries look pretty ancient and simple with no amenities apart from a small snack shop. We left Ko Samui at just after 8am and arrived in Dousak at 9.40am where we got onto another newer bus that took us to a travel agent office in Surat Thani about 68km away. Here we had breakfast even though it was gone 11am and we then got taken to the main bus station and shown to another bus bound for Krabi. We had to wait some 40 minutes for this bus to leave which it finally did at 12.30pm and we arrived in Krabi at 3.40pm.
As donna12 posted, Krabi Airport offers a regular bus service (white buses as you exit the aiport's terminal to the right but you purchase the ticket at the offices after baggage claim), charging 150bahts/person to get to Ao Nang and 90bahts for Krabi-town which they drop off first before continuing on to Ao Nang. It takes about 20 minutes to get from the airport to Krabi-town and another 20 minutes to one end of Ao Nang and they drop off at various points. The ticket seller or bus driver will also ask you when you buy the bus ticket where you want to get dropped off so they'll know which resorts to 'drop' passengers off at.
If it's more than 3 travelers, then it's more practical to just share the taxi all the way from the airport into Ao Nang since it'll be much faster.
When in Ao Nang, you can take a bus tour. To tour around this way has never appealed to me. I like to walk around, take in the sounds and smells. But if you choose to take a bus tour in Ao Nang, this is what the bus may look like!
There are no roads in Railay. Everything is in walking distance and to leave Railay, you need to go by boat. We decided to check out the city just north of Railay which is Ao Nang. About a 15 minute long tail boat ride from Railay. The main town area of Ao Nang is very small. You have a main road traveling along the beach and another road going inland. If you walk up the road going inland you come to a few motorbike rental places. The one we went to had a lavendar colored sign that read Juju Fashion. Sounds strange but I think the sign wasn't changed and no fashions for sale. It cost us 200 baht (US$6.00) to rent the bike for the entire day! The motorbikes are like scooters and are automatic. Seemed easy enough to ride. I rode on the back and not having been on a motorbike before, I opted to use a helmet. We had a blast riding around town and seeing the countryside. Everything is so lush and green.
I agreee with Lotharscheer, Much cheaper and probably a lot faster to take a bus or mini bus, may even be a lot more comfortable considering the time of year that you are planning on going. May can be a bit rough on the ocean with the monsoon rains coming in. You wouldn't even need one of the delux buses, shouldn't take you more than 2 hours at the most to get there and shouldn't cost you more than 100B each for the trip. Ride with the locals, it can be a fun experience! The people will be friendly and helpful.
From the airport, it's convenient to hire a taxi to take you to your destination. When I was there, we shared a taxi with another couple going along the same way and halved our taxi fare (costed us THB1,600). Great way to save! The travel time from airport to Rawi Warin Resort was about 2 hours so I feel it was a very good price I paid.
If you are not in a huge hurry to get around the bay this is an excellent way to travel from the east side of the Andaman Sea to the Phuket (and probably the other way around but i didnt try that). The boat starts out from Krabi, and makes definite stops at West Railay Beach(where we stayed) Ao Nang and one more location i'm not sure of, sorry, before heading straight across the bay to Phuket. We left at 1500 and arrived around 1700. The standard ticket is 550Baht (about 20$ US) so dont be fooled by longtail and speed boat drivers that may try to charge you 1200-2500 baht for a trip. Granted, if your in a hurry speed boat is probably the way to go but if you can afford the time it will definitely be nice on the wallet.
Also the boat is very nice with AC on the bottom inner area with 3 deep seats you can normally lay down in if a nap suits you, or if you're wanting to see alot of nice scenery and have the wind blow through your hair just stay on the top of hte boat, you can even make your way to the front of the top as long as its not too crowded.
It also comes with free soft drinks and crackers, all in all a very pleasent experience.
If travelling in a group of seven, the bargaining power for a fair rental charge to tour around the city is worthy. We had a nice vehicle that transport us to the hotel and later for lunch. The driver even bring us to get a boat charter service, which we can go out to the sea with our own private boat. Service is good.
When you arrive in Krabi Airport, you will see the shuttle bus service counter before you exit. It takes 20 minutes to reach Krabi Town and 40 minutes to reach Ao Nang. Krabi Town costs 90 THB and Ao Nang costs 150 THB. You can use the same shuttle service to reach back to Krabi Airport. It is a better option than taxi if you are not a group of 3 or 4 people travelling together.
We spent a few days in Krabi in March 2008 and used the taxi service of "Mr. A" (Mobile No. 085-7913744). We found him to be a very professional, reliable and safe driver. He speaks very decent English too (having worked at a 5-star hotel previously). Would highly recommend him. If you decide to call him, let him know the couple from Singapore who stayed at the Cliff Ao Nang recommended him.