Best Ultralight Sleeping Bags for Backpacking & Thru-Hiking

Introduction

When every ounce matters, choosing the best ultralight sleeping bag can make a significant difference on long-distance hikes and backpacking trips. These sleeping bags are designed to be lightweight, highly packable, and warm, offering maximum comfort without the extra weight.

In this guide, we’ll explore the top-rated ultralight sleeping bags, covering down vs. synthetic insulation, temperature ratings, and packability. If you’re also looking for a lightweight sleeping pad, check out our Best Ultralight Sleeping Pads to complete your setup.

---

1. What to Look for in an Ultralight Sleeping Bag

1.1 Weight & Packability

• Ultralight sleeping bags weigh between 12-32 oz (0.75-2 lbs).
• Premium down insulation compresses smaller than synthetic fill.
• Stuff sack or compression bag can help reduce bulk.

🔹 Best for weight savings: Look for sleeping bags under 2 lbs with high compressibility.

👉 Pairs well with: Best Ultralight Backpacks for minimal pack weight.

---

1.2 Insulation Type: Down vs. Synthetic

• Down Insulation:
  ✅ Higher warmth-to-weight ratio.
  ✅ More compressible.
  ✅ Best for dry climates.
• Synthetic Insulation:
  ✅ Retains warmth when wet.
  ✅ More affordable.
  ✅ Dries faster than down.

🔹 Best for thru-hikers: Down is lighter and packs smaller, but synthetic is better in damp conditions.

👉 Pairs well with: Best Waterproof Backpack Covers for protection against rain.

---

1.3 Temperature Rating

• 35°F to 50°F (1°C to 10°C): Best for warm summer nights.
• 20°F to 35°F (-6°C to 1°C): Suitable for 3-season backpacking.
• 0°F to 20°F (-17°C to -6°C): Essential for cold-weather camping.

🔹 Best for versatility: A 20°F bag works for most 3-season conditions.

👉 Pairs well with: Best Sleeping Bag Liners for added warmth on cold nights.

---

2. Best Ultralight Sleeping Bags for 2025

1. Best Overall: Western Mountaineering UltraLite 20

• Temperature Rating: 20°F (-6°C)
• Weight: 1 lb 13 oz
• Insulation: 850-fill power down
• Why It’s Great:
  • Extremely warm for its weight.
  • Highly compressible, fits in small packs.
  • Durable ripstop nylon shell.

🔹 Best for all-around ultralight backpacking: Warm, compact, and durable.

👉 Pairs well with: Best Lightweight Backpacking Tents for an efficient setup.

---

2. Best Budget Ultralight Sleeping Bag: REI Co-op Magma 30

• Temperature Rating: 30°F (-1°C)
• Weight: 1 lb 3 oz
• Insulation: 850-fill power down
• Why It’s Great:
  • High-quality down insulation at a lower price.
  • Water-resistant finish for damp conditions.
  • Great warmth-to-weight ratio.

🔹 Best for budget-conscious ultralight hikers: Light, warm, and affordable.

👉 Pairs well with: Best Budget Sleeping Pads for an affordable lightweight sleep system.

---

3. Best for Thru-Hiking: Zpacks 20F Sleeping Bag

• Temperature Rating: 20°F (-6°C)
• Weight: 1 lb 2 oz
• Insulation: 900-fill power down
• Why It’s Great:
  • Ultralight for serious thru-hikers.
  • Highly packable and efficient design.
  • No zipper to save weight.

🔹 Best for thru-hikers: One of the lightest 20°F sleeping bags available.

👉 Pairs well with: Best Ultralight Tents for long-distance hiking.

---

4. Best Synthetic Ultralight Bag: Enlightened Equipment Revelation 20

• Temperature Rating: 20°F (-6°C)
• Weight: 1 lb 5 oz
• Insulation: Synthetic Climashield Apex
• Why It’s Great:
  • Performs well in wet conditions.
  • Quilt-style design adds flexibility.
  • Ultra-packable despite synthetic insulation.

🔹 Best for wet conditions: Synthetic insulation retains warmth when damp.

👉 Pairs well with: Best Waterproof Backpacks for added moisture protection.

---

3. Comparison: Best Ultralight Sleeping Bags

Sleeping Bag	Temperature Rating	Weight	Insulation Type	Best For
Western Mountaineering UltraLite 20	20°F (-6°C)	1 lb 13 oz	Down	Best Overall
REI Co-op Magma 30	30°F (-1°C)	1 lb 3 oz	Down	Best Budget
Zpacks 20F Sleeping Bag	20°F (-6°C)	1 lb 2 oz	Down	Best for Thru-Hiking
Enlightened Equipment Revelation 20	20°F (-6°C)	1 lb 5 oz	Synthetic	Best for Wet Conditions

🔹 Best for ultralight adventurers: Zpacks 20F Sleeping Bag is the lightest choice.

---

4. How to Choose the Right Ultralight Sleeping Bag

1. Consider Your Camping Conditions

• Warm climates: A 35°F+ sleeping bag is sufficient.
• 3-season use: A 20°F bag offers versatility.
• Cold-weather trips: A 0°F sleeping bag ensures warmth.

🔹 Best for multi-season use: A 20°F bag works in most conditions.

👉 Pairs well with: Best Cold-Weather Sleeping Pads for extra insulation.

---

2. Weight vs. Comfort Trade-Off

• For the lightest setup: Choose a quilt or zipperless sleeping bag.
• For more warmth: Get a mummy-style sleeping bag with a snug hood.
• For flexibility: A quilt-style sleeping bag can be used as a blanket.

🔹 Best for comfort: A mummy bag provides better warmth retention.

---

Final Thoughts

Choosing the best ultralight sleeping bag means balancing weight, warmth, packability, and durability.

• For all-around performance: Western Mountaineering UltraLite 20 is the best choice.
• For budget-conscious hikers: REI Co-op Magma 30 provides great value.
• For thru-hikers: Zpacks 20F Sleeping Bag is the lightest option.
• For wet conditions: Enlightened Equipment Revelation 20 offers reliable synthetic insulation.

Looking for more ultralight gear? Check out our Best Ultralight Sleeping Pads to complete your setup!