This border crossing to Malaysia is little known to travellers, but is one of the cheapest ways to get another 30 days on your visa. The crossing is about 2 km further north of the National Park turn-off and costs Bt20 to reach from Satun. There is also a small market here but nothing else. The border is open seven days. This small town marks the junction of Route 416 and the road down to the pier at Pakbara.
Most people end up here for a little while as they wait for their songtheaws to coordinate.
Importantly, La-Ngu has the closest bank to the offshore islands and will exchange travellers checks and give cash advance. The branch is at the Satun end of town, down a road on your right once you have passed the Sri La Ngu Hotel. La-Ngu does have a busting market, which is a great place to buy cheap food if you are planning on spending a while on the islands. The beach here is mainly mudflats and pretty dirty. There are a number of travel agents near to the wharf who can organize tickets to the regional and usual destinations.