Ko Phra Thong is reached either from Saphan Pla pier, just past the Ko Surin National Park pier about 7 km north of the town of Khuraburi, or from a boat launch at Bang Det (also known as "Mangrove pier" or "Southern pier"), which lies about 5 km from Khuraburi town amongst the extensive coastal mangrove canals. While it's possible to hire a longtail from Saphan Pla pier and show up at Ko Phra Thong unannounced, probably the better idea is to phone ahead to your resort of choice, in which case they will help arrange boat transport and give you a lift by motorbike from which ever pier you arrive at. If needing some direction, stop by Tom and Am Tour or Boon Piya Resort in the centre of Khuraburi, who are happy to arrange a motorbike taxi or songthaew from Khuraburi to the pier and call ahead to any of the resorts.
Tom and Am Tour may be contacted at (086) 272 0588 or firstname.lastname@example.org.
Boon Piya Resort may be contacted at (081) 752 5457 or (076) 491 969.
Unlike many of Thailand's more frequented islands, there is no single "go to" transport option for Ko Phra Thong. There is a local ferry that departs from Bang Det, usually very early in the morning, but due to it not consistently departing everyday and at different times when it does, it's not a good option unless specifically suggested by one of the resort owners on Ko Phra Thong who are up to date on when and if it's departing.
If it is, the cost should be 250B not including transport to the boat launch. The same boat returns to Khuraburi from the pier at Ta Pai Yoe most days around 8:00, although you'll want to check with your resort before banking on that. The resorts on Phra Thong will charge an additional 100B — so 350B total for the trip — that covers a motorbike ride to the pier and a songthaew from Bang Det to the bus station in Khuraburi. This might seem steep for a songthaew ride, but it's clearly how things work here, so if foregoing the 100B to your resort don't be surprised if you have no way of getting from Bang Det to Khuraburi after arriving, and it's not an easy route to figure out on your own.
Another option from Khuraburi, which again must be suggested and arranged by Mr. Chuoi or another of Phra Thong's resorts, is to take a local banana boat for 400B. This is a very small boat just big enough for one big passenger with a big pack or maybe two smaller passengers with little in tow, but it could be a more adventurous way to get to the island while saving a little money.
The other way — and the way that's often first recommended by the tour companies and sometimes said to be the only way although that's not true — is to pay 1,000B for a one-way longtail from either Saphan Pla pier or Bang Det. While expensive for solo or duo travellers, this isn't a bad choice for groups since 1,000B should cover up to four people. Again, it's best to arrange this in advance to ensure there's a boat waiting. Although, when we just showed up at Saphan Pla pier and asked around we were able to locate a local longtail driver who offered to make the run for 1,000B. His name is Date, and although he speaks little English, you could give him a try if you find yourself at the pier without a boat. His number is (089) 972 1747.
From Ko Phra Thong, any resort can arrange a longtail transfer for 1,000B. It's also worth mentioning that Golden Buddha has their own boats and typically arrange transport for their guests to and from the island. Particularly if the local boat isn't running for some reason, it would be smart to check in at Golden Buddha and ask if you can hop in with one of their boats for cheaper than the 1,000B private boat.
Ko Phra Thong is large and flat, and if looking to explore it's possible to rent motorbikes (300B) or bicycles (50-100B) at Mr. Chuoi's or Lions Village. We found it particularly suitable for bicycle, but take note that there are no convenience shops selling water along the long stretches between the villages and resorts, so be certain to take enough water as it can get very hot. Because of its large size, walking is not a particularly good way to get around between villages, but all of the resorts and Blue Guru's dive shop are within walking distance along the northern beaches.