Below is a comprehensive to-do list for exploring Don Det, part of the Si Phan Don (4,000 Islands) region in southern Laos. Don Det is renowned for its laid-back vibe, stunning Mekong River views, and unique backpacker culture. I’ll outline the main activities, how to do them, helpful tips, and relevant details for the most fulfilling experience. I've translated it into English and removed any website suggestions as requested.

1. Relax on a Hammock by the Mekong River

• Description: Don Det is famous for its slow-paced lifestyle. One of the best activities is lounging in a hammock at a riverside bungalow, watching the sunset or sunrise over the Mekong River. It’s the perfect way to soak in the island’s tranquility and natural beauty.
• Details:
• Locations: Riverside bungalows on either side of the island (sunset side or sunrise side). The sunset side is livelier with bars and restaurants, while the sunrise side is quieter, ideal for relaxation.
• Suggested Accommodations:
• Mama Leuah Guesthouse: Cozy bungalows with sunrise views, priced around $10-14/night.
• Easy Go Backpackers: Friendly vibe with free bikes to explore the island.
• The Boathouse: Quiet bungalows in the south, reasonably priced.
• Tips:
• Choose a bungalow with a hammock on the balcony for maximum relaxation.
• Bring a book or headphones, as Wi-Fi can be unreliable.
• Book in advance during peak season (November-February), as bungalows fill up quickly.
• Cost: Bungalows range from $5-$30/night depending on amenities (fan or air conditioning).

2. Cycle Around Don Det and Don Khon

• Description: Cycling is a fantastic way to explore Don Det and nearby Don Khon, connected by an old French-built iron bridge. You’ll see countryside views, rice fields, and local villages.
• Details:
• Routes:
• Don Det Loop: A 7.2 km trail around the island, easy to ride with scenic views.
• Don Khon: Cross the Old French Railway Bridge to visit attractions like Li Phi Waterfall (Tat Somphamit), Khon Pa Soi Waterfall, and Wat Khon Tai temple.
• Bike Rentals: Available at most guesthouses or shops, costing about 10,000-15,000 kip ($0.5-$1) per day.
• Key Attractions:
• Old French Railway Bridge: A historic iron bridge connecting Don Det and Don Khon, once part of a French railway for transporting goods. Stop for photos or to see abandoned train engines.
• Li Phi Waterfall (Tat Somphamit): A beautiful waterfall on Don Khon, about 10 minutes by bike from the bridge. It has areas for swimming and relaxing, but be cautious of strong currents.
• Khon Pa Soi Waterfall: Less crowded, ideal for a peaceful visit.
• Tips:
• Wear a hat and sunscreen, as it can get very hot, especially from March to May.
• Check the bike’s brakes and tires before renting.
• During the rainy season (May-October), paths may be muddy but still manageable for an adventurous ride.
• Cost: Bike rental $1/day, bridge crossing fee to Don Khon about 20,000 kip ($1) if not staying there.

3. Kayak on the Mekong River

• Description: Kayaking is one of the most exciting activities on Don Det, allowing you to explore nearby islands, waterfalls, and even visit the Cambodian border.
• Details:
• Popular Tours:
• Full-Day Kayaking Tour: Typically starts at 8:30 AM, including breakfast, lunch, equipment (life jackets, kayaks), and a guide. Destinations include E-Toud Waterfall, Khone Phapheng Waterfall (Southeast Asia’s largest by volume), and small islands like Don Som.
• Sunset Tour: A shorter afternoon kayak trip, combined with watching the sunset on the Mekong.
• Booking Locations:
• Available through guesthouses or local operators in Don Det’s center, such as those run by Mr. Boun or Mr. Mo.
• Highlights:
• Paddle through small channels and pristine islands, soaking in rural scenery and local life.
• Stop at a small island for lunch (often Lao-style BBQ with grilled fish, potatoes, and salad).
• Visit Khone Phapheng Waterfall to witness the Mekong’s power. Entry fee is about 55,000 kip ($2.5).
• Tips:
• Bring a waterproof bag to protect cameras and phones, as currents can be strong.
• Wear clothes and shoes that can get wet, plus a hat and sunscreen.
• Book a day in advance to secure a spot, especially during peak season.
• Cost: $20-$26/person for a full-day tour, including meals and equipment.

4. Enjoy Sunset and Drinks at Riverside Bars

• Description: Don Det is known for its stunning sunsets, and there’s nothing better than sipping a BeerLao or cocktail at a riverside bar on the sunset side of the island.
• Details:
• Top Spots:
• Happy Bar Backpackers: A lively bar with a fun vibe, often organizing boat trips to a small island for bonfires and games. Manni, the manager, adds to the unique experience.
• Namfon Sunset Restaurant: Popular for affordable, simple meals and great sunset views. Their veggie burgers are highly rated.
• Mojo: An Italian spot with sunset views, serving tasty pizza and pasta.
• Tips:
• Arrive early (around 5 PM) to secure a good spot, as bars can get crowded during peak season.
• Be cautious with “happy” menu items (containing cannabis), as cannabis is illegal in Laos. Ask other travelers for advice.
• Bring cash, as there are no ATMs on the island, and some places don’t accept cards.
• Cost: BeerLao $1-$2, cocktails $2-$4, light meals $2-$5.

5. Visit Khone Phapheng and Other Waterfalls

• Description: The 4,000 Islands region is famous for its spectacular waterfalls, particularly Khone Phapheng, Southeast Asia’s largest by water volume.
• Details:
• Khone Phapheng Waterfall:
• Location: On the mainland, about 20 minutes by tuk-tuk from Nakasang.
• How to Get There: Join a kayaking tour or hire a tuk-tuk from Nakasang ($5-$10 round trip).
• Highlights: A majestic waterfall with powerful flows, offering a stunning spectacle. Entry fee is about 55,000 kip ($2.5).
• Li Phi Waterfall (Tat Somphamit):
• Location: On Don Khon, easily accessible by bike or foot from the bridge.
• Highlights: A scenic waterfall with areas for swimming and relaxing. Cross a slightly risky wooden bridge to reach it, so tread carefully.
• Khon Pa Soi Waterfall:
• Location: Also on Don Khon, less crowded and perfect for a quiet visit.
• Tips:
• Combine waterfall visits with a kayaking tour to save time and money.
• Wear non-slip shoes if swimming or walking near waterfalls, as rocks can be slippery.
• Cost: Khone Phapheng entry $2.5; Li Phi and Khon Pa Soi are free (except for the Don Khon bridge fee if applicable).

6. Go Tubing on the Mekong River

• Description: Tubing (floating on an inflatable tube) is a relaxing way to drift along the Mekong, enjoy the scenery, and stop at riverside bars for a BeerLao.
• Details:
• How to Do It: Rent tubes at shops or guesthouses near Don Det Beach on the north side. Cost is about 10,000-15,000 kip ($1).
• Starting Point: Usually from Don Det Beach, or hire a boat to tow you upstream for a longer float.
• Tips:
• Avoid excessive drinking while tubing, as currents can be strong and dangerous, especially near waterfalls like Li Phi Falls (500m from the French bridge).
• Stop before the Don Det-Don Khon bridge to avoid strong currents.
• Wear a life jacket if you’re not a confident swimmer.
• Cost: Tube rental $1, optional boat tow $2-$5.

7. Savor Local and International Cuisine

• Description: Don Det offers a variety of restaurants serving traditional Lao dishes and international options like Indian, Italian, and vegetarian, all budget-friendly.
• Details:
• Must-Try Dishes:
• Lao BBQ: Grilled fish or meat with potatoes and salad. Ask at places like Mama Leuah or Happy Bar.
• Larb Gai: A spicy Lao chicken salad, about $2-$3.
• Indian Curry: Datta Banana Leaf Restaurant is known for curries and naan.
• Vegetarian Options: Garden of Eden Vegan Restaurant offers spring rolls and veggie curries.
• Recommended Restaurants:
• Datta Banana Leaf: Tasty, affordable Indian food.
• Mama Tanon: Cheap breakfast ($2) with Mekong views.
• Mama Leuah: Lao cuisine in a friendly setting near the river.
• The Garden Riverside: Great iced coffee and a slightly upscale vibe.
• Tips:
• Order in advance if you want quick service, as some restaurants can be slow (fitting the island’s laid-back pace).
• Be cautious with “happy” dishes due to legal risks with cannabis.
• Cost: Meals $2-$5, drinks $1-$4.

8. Explore Local Culture and History

• Description: Don Det and Don Khon offer cultural and historical sites, especially from the French colonial era and Buddhist traditions.
• Details:
• Wat Khon Tai Temple: On Don Khon, a Buddhist temple built on an ancient Khmer site, featuring stupas and Khmer relics. Great for history buffs.
• Old French Railway: Explore remnants of a narrow-gauge railway built by the French in 1893 to bypass waterfalls. Old train engines near the Don Det-Don Khon bridge make for great photos.
• Buddhist Almsgiving: Early mornings, you may see young monks collecting alms around the village, a beautiful traditional ritual.
• Old French Port: In southern Don Khon, once a spot to view Irrawaddy dolphins (now extinct in Laos). You can see Cambodia from here and enjoy drinks at nearby stalls.
• Tips:
• Dress modestly when visiting temples to respect local culture.
• Learn about French colonial history beforehand for a richer experience.
• Cost: Free (except for the Don Khon bridge fee if applicable).

9. Swim in the River or a Pool

• Description: Cool off in the Mekong River or pay to use a pool at certain guesthouses to beat the Don Det heat.
• Details:
• River Swimming: Safe swimming spots are available near Don Det Beach or during kayaking tours (e.g., near E-Toud Waterfall). Be cautious of strong currents.
• Pools:
• Little Eden Guesthouse and Resort: Offers a nice pool for about $2-$3 if you’re not a guest.
• Long Island Guesthouse: Provides a pool and sunbeds for a similar price.
• Tips:
• Check with locals or guides for safe swimming areas.
• Bring a towel and swimwear.
• Cost: River swimming is free, pool access $2-$3/person.

10. Join Community Events and Parties

• Description: Don Det has a vibrant backpacker community, with opportunities to join bonfire parties, games, or mingle with locals and travelers.
• Details:
• Happy Bar’s Island Trip: Manni at Happy Bar organizes boat trips to a small island for bonfires, games (like obstacle courses or beer challenges), and river swimming. A unique experience loved by travelers.
• G-Spot Mini Golf: A fun mini-golf course on the island, great for socializing.
• Reggae Bar: Hosts island BBQ parties with a lively, friendly atmosphere.
• Tips:
• Check event schedules at bars or guesthouses for spontaneous activities.
• Chat with other travelers for tips on pop-up events.
• Cost: Party or boat trip participation $5-$10, depending on the event.

11. Stargaze and Enjoy Nature

• Description: With electricity only recently available 24/7, Don Det has minimal light pollution, making it perfect for stargazing at night.
• Details:
• Locations: Relax in a hammock at your bungalow or head to Don Det Beach to stargaze.
• Wildlife: Spot glowing insects (like Elateroidea beetles) or animals such as geckos, butterflies, and beetles.
• Tips:
• Bring a flashlight or headlamp for nighttime movement, as some areas lack streetlights.
• Consider a nature tour with a local guide for a deeper wildlife experience.
• Cost: Free.

General Tips for Visiting Don Det

• How to Get There:
• From Pakse: Take a minivan or bus (3-4 hours, $10-$11) to Nakasang, then a 15-20 minute boat ride (30,000 kip/$1.5) to Don Det.
• From Siem Reap (Cambodia): Take a bus (8-12 hours, $20), including the ferry.
• From Vientiane: Take an overnight bus (10-12 hours) or fly (45 minutes, $30+) to Pakse, then proceed as above.
• Best Time to Visit: Dry season (November-February) for pleasant weather. Avoid March-May due to intense heat.
• Preparation:
• Bring enough cash (Lao kip), as there are no ATMs on the island. Withdraw money in Pakse or Nakasang beforehand.
• Wi-Fi is unreliable, so prepare for a digital detox.
• Pack light, with comfortable shoes, sunscreen, and a waterproof bag.
• Local Culture:
• Respect Laos’ 11 PM curfew; bars typically close early.
• Avoid cannabis-related activities to steer clear of legal risks.
• Suggested Stay: 3-5 days to fully experience the activities and relax.

Suggested 3-Day Itinerary for Don Det

• Day 1: Arrive at Don Det, check into a bungalow, relax in a hammock, and enjoy sunset at Happy Bar or Namfon Sunset Restaurant.
• Day 2: Cycle around Don Det and Don Khon, visit Li Phi Waterfall, Khon Pa Soi Waterfall, and Wat Khon Tai. Spend the evening stargazing or socializing at Reggae Bar.
• Day 3: Join a full-day kayaking tour, visit Khone Phapheng Waterfall, enjoy a BBQ lunch on a small island, and end with dinner at Datta Banana Leaf.

Don Det is perfect for those seeking relaxation, nature, and a unique backpacker experience. With activities ranging from kayaking and cycling to sunset drinks and local cuisine, you’re sure to have a memorable trip. Let me know if you need more details or a tailored itinerary!