I’ve been to Ranong ( Myanmar ) and back ( last year ) in a day .
As mentioned agents can organise , by using an agent they explain and go with you etc , it’s all in groups , boat 15 minutes each way . Stood in Kawthoung ( Myanmar ) for about 10-12 minutes
Ranong immigration is actually the water border to Myanmar .
Fly to Malaysia and back
Or you can get a train to Hat Yai then train into Malaysia
The ask:thailand community, consisting of multiple Q/A groups with over 100,000 members, powers this platform. It is not an official government resource. Our members actively contribute to this resource, and while we strive for accuracy, we cannot guarantee its complete reliability. Assistance to travelers is provided as a community service.