The Similan Islands is an archipelago a few miles west of Khao Lak in the Andaman Sea. You can get there from the Tab Lamu Port with a 3-hour boat ride, though speedboats can make the trip in just over an hour. Once you arrive, you'll find yourself in Similan Islands Park, a national park with well-protected greenery and scenic views. Just be aware that it can get quite crowded at times, and it's closed during the rainy season.
International Tsunami Museum
The International Tsunami Museum is dedicated to preserving the 2004 Boxing Day Tsunami that struck the area. Within the museum, the exact timeline of events is documented, and you can see actual relics from the destruction that this massive tsunami caused. Tales from survivors are preserved here as well, along with other fascinating stories from the post-disaster period.
Samet Nangshe Viewpoint
Samet Nangshe Viewpoint is an iconic observation point where you can take in the scenic Phang Nga Bay. It's a fairly secluded location, so the light pollution from cities and towns doesn't have that much effect here. Because of this, nighttime visits allow you to peer up into the wider galaxy, and the Milky Way is visible on particularly clear nights.
Takua Pa Old Town
Takua Pa Old Town is a historic area in the region known for its unique Chino-Portuguese architecture, a design stemming from the colonial days of the area. While once a mining town, the modern community is much more laid back and simplistic, boasting fun shops and markets throughout. Food is especially important here, making it a great place to try the local cuisine.