Gulf of Thailand vs Andaman Sea: Which Coast Is Actually Better?

I’ve spent real time on both and I have opinions

This is probably the most common Thailand planning question and most guides give you a wishy-washy “it depends on what you want” answer. I’ll try to be more direct.

The Andaman (west) looks better on Instagram

Koh Phi Phi, Krabi, the karst limestone islands — this is the Thailand of magazine photos. The scenery is dramatically more striking than the Gulf side. Phang Nga Bay is genuinely one of the most beautiful places I’ve ever seen. If visual drama is what you’re after, the Andaman wins easily.

The Gulf (east) is better for actually being underwater

Koh Tao specifically has some of the best dive training value in the world — Open Water certification for around ฿10,000 (around $280) in a place with reliably good visibility. The Gulf islands have a more established dive infrastructure and are better for serious divers. I did my Open Water in Koh Tao and would do it again in a heartbeat.

The season question

This is where it actually matters. During Thailand’s monsoon season, the two coasts are affected at different times. The Andaman gets heavy rain May–October; the Gulf gets it October–January. Roughly speaking: November–April is great for both; outside that, choose the coast that’s in dry season.

I almost ruined a trip by going to Koh Lanta in October — technically still “Andaman season” by some guides but in practice the rain was relentless and half the restaurants were closed. Check actual monthly weather forecasts, not just “best time” summaries.

My honest take

First-time Thailand beach trip with good weather: Andaman coast, specifically Koh Lanta or Krabi area. Repeat visit or diving-focused: Gulf coast and Koh Tao. Parties: Koh Phangan. Families: Koh Samui or Bang Tao, Phuket.