Andaman Sea Travel Guide: Islands, Diving & Resorts

Stretching over 800 kilometres along Thailand's southwestern flank, the Andaman Sea drops to depths exceeding 3,000 metres while housing underwater limestone pinnacles that lure whale sharks and manta rays. This body of water hosts more than 20 marine national parks, stretching from the Burmese border at Ranong down to the Malaysian maritime frontier off Satun.

The Andaman Sea forms the eastern arm of the Indian Ocean, bordering Thailand's western coastline across six provinces: Ranong, Phang Nga, Phuket, Krabi, Trang, and Satun. Characterised by karst topography, clear emerald waters, and shallow coral reefs, it attracts scuba divers, island-hoppers, and coastal travellers seeking diverse marine environments. Major departure nodes like Phuket, Khao Lak, and Krabi connect mainland transit hubs to remote island archipelagos. The coastline caters to every style of traveller, offering everything from off-grid national park campgrounds to ultra-luxury private peninsula resorts.

Southwestern Coastline and Marine Geography

The Andaman coastline of Thailand spans 840 kilometres of jagged limestone karsts, mangrove forests, and isolated island archipelagos. Moving south from Ranong's coastal estuaries, the coastline transitions into the granite formations of the Similan Islands before giving way to the massive submerged karst towers of Phang Nga Bay and Krabi's Railay peninsula. Further south, the Trang coastline features low-lying mangrove-ringed islands that finally connect with the dramatic rock formations of the Mu Ko Tarutao Marine National Park near Satun. Tides along this western sea are semi-diurnal, creating distinct water movements that flush nutrients into deep channels, feeding vast coral ecosystems. Coastal water temperatures remain stable between 28°C and 30°C year-round. Navigating these waters requires awareness of monsoon cycles, as heavy south-westerly swells close offshore access to outer island chains between May and October. Map your route along specific provincial hubs, as ferry connections operate regionally rather than along a single continuous marine corridor.

Key Marine Parks and Island Groups

Protected marine national parks preserve Thailand's richest coral habitats and distinct offshore island ecosystems. The Surin Islands (Mu Ko Surin National Park) sit 60 kilometres off Phang Nga province, featuring shallow reefs populated by clownfish, sea turtles, and Moken sea-gypsy settlements. Entrance fees to marine parks cost 400 THB (£9.20) for adult foreigners, plus a daily 20 THB (£0.45) maintenance fee. South of Surin lie the nine granite islands of the Similan chain, renowned for clear granite formations and visibility reaching up to 30 metres underwater. These northern parks strictly limit daily visitor numbers and completely close from 16 May to 15 October each year. In the far south, Mu Ko Tarutao National Park covers 51 islands near Malaysia, including Ko Adang and Ko Lipe, where dense jungles merge directly into living reef systems. Book marine park permits and speedboats several weeks in advance for Mu Ko Similan, as daily capped entry slots sell out rapidly during peak winter months.

Southern Seafood Culture and Regional Dining

Dining along the Andaman coast relies on intense southern spicing paired with daily catches brought directly into local fishing piers. Coastal southern Thai cuisine heavily features bird's-eye chillies, fresh turmeric, and fermented shrimp paste. Signature regional dishes include Gaeng Som (southern sour yellow curry cooked with snapper or sea bass and green papaya) for 180 THB (£4.15), and fresh mantis shrimp garlic-fried at market stalls for around 350 THB (£8.00) per portion. At established dining spots like Lae Lay Grill perched above Ao Nang in Krabi, diners order whole steamed lime and chilli rock lobster for 1,200 THB (£27.50) while looking out over the Andaman horizon. Smaller piers like Thap Lamu in Phang Nga or Pak Bara in Satun feature humble waterfront eateries where blue swimmer crabs cost 400 THB (£9.20) per kilo. Local night markets in Phuket Town and Trang offer charcoal-grilled squid on skewers for 40 THB (£0.90) alongside spicy sea-grape seaweed salads. Order fish dishes Gaeng Som or turmeric-fried fish at pier-side seafood markets for authentic local flavour profiles without Westernised sweetness.

Diving Routes and Offshore Liveaboards

Deep oceanic drop-offs and nutrient-rich currents position the Andaman Sea among global top-tier scuba diving destinations. Multi-day liveaboard cruises departing from Khao Lak or Chalong Pier in Phuket serve as the primary gateway to remote northern dive sites. A standard 4-day, 4-night liveaboard itinerary targeting the Similan and Surin islands costs between 22,000 THB (£505) and 45,000 THB (£1,035) including meals and dive guides. The crown jewel of these routes is Richelieu Rock, a horseshoe-shaped submerged pinnacle discovered by Jacques Cousteau, famous for pelagic sightings including whale sharks, manta rays, and barracuda schools. Day dives from Ao Nang or Ko Lanta visit Hin Daeng and Hin Muang, submerged rocks offering vertical drop-offs past 60 metres covered in purple soft corals. Water conditions peak between December and March, offering visibility up to 30 metres and mild surface swells. Secure your liveaboard space at least four months ahead if travelling between December and February, as top-rated dive boats operating in the northern parks fill up well before the season opens.

Regional Transit and Coastal Transport

Reaching the Andaman coast from Bangkok is fast via daily domestic flights to major air gateways including Phuket Airport (HKT), Krabi Airport (KBV), or Trang Airport (TST), taking 1 hour 25 minutes and costing roughly 1,500 THB (£34.50). Alternatively, long-distance VIP 24-seater buses run overnight from Bangkok's Southern Bus Terminal (Sai Tai Mai) directly to coastal hubs like Khao Lak, Ao Nang, or Satun’s Pak Bara Pier in 12 to 14 hours for 950 THB (£21.80). Getting around between islands and mainland piers relies on a structured maritime network. High-speed catamarans run by operators like Bundhaya Speedboat and Satun Pakbara Speed Boat connect Phuket, Ko Phi Phi, Ko Lanta, Ko Ngai, and Ko Lipe along a continuous sea route, charging around 1,200 THB to 2,500 THB (£27.50–£57.50) depending on distance. Local wooden longtail boats handle short coastal transfers and private beach hops, costing around 1,500 THB (£34.50) per day for charter. On mainland hubs, Grab rides and local songthaew trucks provide simple land transit.

Travel Budgets and Daily Costs

Travelling along the Andaman Coast accommodates various spending styles, though island locations generally carry a 20% to 30% mark-up over mainland prices due to transport logistics. Budget travellers staying in basic bamboo bungalows or hostel dorms, eating at local night markets, and using public ferries can get by on 1,200 THB to 1,800 THB (£27.50–£41.40) per day. Mid-range visitors staying in air-conditioned beach resorts, dining at established seafood restaurants like Lae Lay Grill, taking day trips, and chartering private longtail boats should budget 3,500 THB to 6,000 THB (£80.50–£138.00) daily. Premium travellers indulging in high-end stays at properties such as Rayavadee in Krabi (where rooms exceed 22,000 THB / £505 per night), fine dining, and private speedboats will spend upwards of 15,000 THB (£345.00) per day.

Visitor Match and Travel Style

The Andaman coastline suits island-hoppers, certified scuba divers, and coastal travellers who value diverse marine environments and dramatic natural topography. It works well for backpackers following established ferry routes, couples seeking high-end cliffside resorts, and marine enthusiasts eager to explore national parks. However, it is less suitable for travellers looking for cheap inland cultural circuits, those seeking quiet off-grid travel during the monsoon months, or visitors prone to severe seasickness who plan to cover large maritime distances during choppy inter-island transit periods.

Key Maritime Rules and Seasonal Facts

National marine parks strictly enforce seasonal closures from 16 May to 15 October annually. This rule protects marine ecosystems during southwest monsoon swells and means islands like Similan and Surin are completely inaccessible during these months. Cash remains mandatory for entry fees and small island transactions across smaller hubs. National park wardens collect 200 THB to 400 THB (£4.60–£9.20) in cash upon arrival at protected islands regardless of your tour package inclusions. Marine protection laws prohibit single-use plastics and non-reef-safe sunscreens inside national park zones. Possessing non-compliant sunblock can result in confiscation and steep fines at park entry checkpoints. Ferry timetables change dramatically between peak dry season and the monsoon season. High-speed island-hopping routes operating between Ko Lanta and Ko Lipe cease operations entirely from May through October.

Practical Advice for Coastal Travelling

Carry dry bags for all boat transfers between mainland piers and smaller island beaches. Waves frequently spray over longtail boat gunwales and wet landing drops require walking through waist-deep surf.

Book liveaboard dive trips several months in advance for peak season months between December and February. Top operators running trips out to Richelieu Rock cap vessel capacities and fill up early.

Pack reef-safe sunscreen that uses zinc oxide or titanium dioxide before arriving at island marine parks. Local shops on smaller islands charge inflated prices for compliant sun protection products.

Keep small cash denominations like 20 THB, 50 THB, and 100 THB notes accessible for national park fees and local longtail boat drivers. Most longtail boat captains cannot break 1,000 THB notes when dropping off at remote coves.

Download offline marine maps and weather forecasting apps like Windfinder before setting sail on long inter-island ferry legs. Mobile coverage drops in deep channels between the mainland and outer archipelagos like the Surin Islands.

Wear quick-drying water shoes when getting on and off longtail boats at low tide. Sharp coral fragments and sea urchins rest on shallow rocky seabeds around island landing zones.

Andaman Coast At-A-Glance