Sea to Summit Ascent 30 — Sleeping Bag Dossier
Published · Researched 2026-09-21
Lineup note: New item for the Sleep Systems research track (2026-09-20). Not part of the existing 22-item catalog. Generation lock: current Ascent 30°F model (2025–2026). The legacy Ascent 25 is documented as predecessor only — never merge specs.
Identifiers
- Brand: Sea to Summit
- Model: Ascent 30 (current; Ascent 15 is the colder sibling)
- Category: Sleeping bag — 3-season down mummy, relaxed cut, Free Flow zip system
- Slug:
sea-to-summit-ascent-30
Version Lineage (2023–2026)
- Legacy Ascent 25 (pre-2025): ~857–930 g / 30.2–32.8 oz depending on size; 750+ Ultra-Dry down; EN Lower Limit 25°F / −4°C, EN Comfort 35°F / 2°C; historical review price $369, later old-stock listings $419. Discontinued in favor of the new range.
- Current Ascent 30 (2025–2026): Regular 782 g / 27.6 oz, 300 g / 10.6 oz fill; ISO Lower Limit 30°F / −1°C, ISO Comfort 38°F / 3°C. Ref: seatosummit.com product page (observed 2026-09-20).
- Current Ascent 15 (2025–2026): Regular 1,020 g / 36 oz, 540 g / 19 oz fill; ISO Lower Limit 15°F / −9°C, ISO Comfort 29°F / −2°C.
- Some retailers still show legacy-flavored spec rows (e.g., CampSaver lists "EN Comfort 29°F" on a 30°F Ascent page) — treat retailer spec tables as suspect; the official current figures govern.
Overview
The Ascent 30 is Sea to Summit's versatile 3-season down bag: a relaxed mummy cut (roomier than most), 750+ RDS down with Ultra-Dry hydrophobic treatment, and the signature Free Flow zip system — a full-length double-slider main zip plus a half-length second zip that lets the bag vent, open flat into a quilt, or be worn at camp with the footbox open. ISO-tested, well-featured (draft collar, technical hood sized for a StS pillow, QuiltLock compatibility), and priced at $429. Backcountry reviewers rate it ~4.9/5 across 30+ reviews.
Key Specs
| Spec | Current Ascent 30 (Regular) |
|---|---|
| Published temp rating | 30°F / −1°C |
| ISO/EN standard | ISO 23537: Lower Limit 30°F / −1°C, Comfort 38°F / 3°C (official current) |
| Weight | 782 g / 27.6 oz (Regular) |
| Fill weight | 300 g / 10.6 oz |
| Fill | 750+ fill-power RDS goose down with Ultra-Dry Down hydrophobic treatment |
| Shell / lining | 20D recycled nylon; 10D waterproof-breathable nylon hood and footbox |
| Max user height | 185 cm / 6'1" (Regular) |
| Packed size | ~8 L compressed |
| Shape | Wide/relaxed mummy |
| Zippers | Free Flow full-length double-slider main zip + half-length secondary zip + footbox zip; YKK; down-filled draft tubes on all zips |
| Extras | Adjustable draft collar, technical hood (fits regular StS pillow), QuiltLock quilt-attachment system, toe anti-pinch guard |
Price
- MSRP observed 2026-09-20: $429.00 USD (gearfool.com, 30°F/Regular; Long sold out; CampSaver lists Long at $429.00).
- Street price: ~$429 at US specialty retailers; EU/UK listings ~£296–£348 / CHF ~334–430. Backcountry showed out of stock at time of crawl.
- Legacy Ascent 25 old-stock: ~$419 — do not confuse with current pricing.
In the Box
- Sea to Summit Ascent 30 sleeping bag
- Compression stuff sack
- Storage sack (confirm — StS typically includes both)
Warranty
- Sea to Summit warranty against manufacturing defects. Exact current terms UNVERIFIED — confirm on seatosummit.com.
Support & Parts
- Sea to Summit customer service; repair network varies by region. Details UNVERIFIED.
Community Verdict
- Backcountry (observed 2026-09-20): 4.9/5 across 34 reviews (unisex) and 4.96/5 across 26 reviews (women's) — exceptionally strong retail ratings. Reviewers praise the roomy cut, ventilation options, and damp-weather performance.
- General community: the Ascent line is a long-standing recommendation for backpackers wanting one bag that spans summer to shoulder season, thanks to the Free Flow venting.
- Criticisms: at 782 g it's heavier than boutique 30°F bags; 750+ fill is good-not-great per ounce; some find the feature set (multiple zips) fiddly.
- Reddit/Facebook/Threads/Instagram pulse: UNVERIFIED — targeted social-platform extraction not captured; do not invent.
Image Paths
images/sea-to-summit-ascent-30-1.jpg— mfr, ASCENT -1C/30F printedimages/sea-to-summit-ascent-30-2.jpg— green full bagimages/sea-to-summit-ascent-30-3.jpg— women's full bagimages/sea-to-summit-ascent-30-4.jpg— storage cube, model printedimages/sea-to-summit-ascent-30-5.jpg— women's storage cubeimages/sea-to-summit-ascent-30-6.jpg— women's storage cube detail
Long-Term Durability & Warranty-Claim Reality
- Ultra-Dry Down treatment's wash-cycle longevity: UNVERIFIED — hydrophobic treatments generally degrade over washings industry-wide.
- Multiple zippers = multiple snag/failure points; YKK quality mitigates but the Free Flow system needs zipper care.
- Specific warranty-claim outcomes: UNVERIFIED.
Year-by-Year Version History
| Year | Change |
|---|---|
| Pre-2023 | Ascent 25 (EN LL 25°F); $369 review pricing |
| 2023–2024 | Ascent 25 continued; old-stock at $419 |
| 2025–2026 | Range reset: Ascent 30 (ISO LL 30°F, 782 g, 300 g fill) and Ascent 15 (ISO LL 15°F, 1,020 g, 540 g fill); $429 USD |
Head-to-Head vs Existing Catalog Rivals
- vs
/library/gear/sleep-systems/big-agnes-diamond-park-30/— Both 30°F bags; the Ascent 30 is lighter, more compressible (down), and has the Free Flow venting system; the Diamond Park is roomier and cheaper. Backpackers pick Ascent; car campers pick Diamond Park. - vs
/library/gear/sleep-systems/kelty-cosmic-down-40/— The Ascent 30 is the warmer, roomier, better-featured step up (~2× the price). Cosmic for summer value; Ascent for true 3-season versatility. - vs
/library/gear/sleep-systems/nemo-disco-15/— The Disco 15 is warmer-rated and spoon-shaped; the Ascent 30 is lighter with superior venting. Disco for cold side-sleepers; Ascent for adaptable 3-season use.
Care & Maintenance
- Wash with down-specific detergent, front-loader, extra rinses; dry low with dryer balls until fully lofted.
- Store uncompressed; air out after trips.
- Keep all zippers clean and occasionally waxed; use the draft tubes' protection when stuffing.
Buying Traps
- Ascent 25 vs Ascent 30: same product family name, different ratings and weights — verify the "30" and ISO figures on the tag.
- Retailer spec tables may carry legacy EN rows — trust the official current page.
- Women's vs unisex: Backcountry lists both; women's cut is a relaxed mummy tuned for women — confirm which you're buying.
- 750+ fill at 782 g is not ultralight — boutique 30°F bags are lighter; you're paying for features and room.
Community Verdict — Additional Voices
- EU/UK retailers (Ekosport, Hardloop) list the current Ascent 30 with consistent specs (782 g, comfort 3°C, limit −1°C), corroborating the official figures.
- The bag's "wear it at camp" mode (footbox open, snaps at shoulders) is a genuine differentiator owners mention.
Key Specs — Gap Fill
- Long-size weight/fill: UNVERIFIED (CampSaver Long page: 897 g — conflicts with Regular 782 g plausibly; treat as size variance, unverified officially)
- Storage sack inclusion: unconfirmed
- Official warranty terms: UNVERIFIED
Research date: 2026-09-20. Specs and prices observed 2026-09-20; UNVERIFIED items flagged inline.