Earth River SUP 8-9 RIVER S3R-MKII - NEPTUNE Inflatable Paddle Board (8'9"x35"x6")
Earth River SUP 8-9 RIVER S3R-MKII - NEPTUNE Inflatable Paddle Board (8'9"x35"x6")Couldn't load pickup availability
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The Earth River SUP 8-9 RIVER S3R-MKII is the compact size of ERS's dedicated whitewater board — 8'9" long, 35" wide, 6" thick, and just 19 lb. Like its 9'7" sibling, it's designed to excel at all areas of river paddling: attaining upstream to play spots, river surfing, running rapids, creeking, and expeditions.
Who Is The 8-9 RIVER For?
The 8-9 RIVER is for river paddlers who want the S3R-MKII's whitewater shape in its shortest, lightest form. The compact length is naturally suited to quick direction changes on a wave and in tight water, and at 19 lb it's easy to carry down a bank, portage around a drop, or hike to a remote put-in.
Like the 9-7, it's the same purpose-built river board underneath — the same ULTRA RIVER construction, the same short-fin setup, the same 48-month warranty.
8'9" | 35" wide | 6" thick | 19 lb board weight | Riders up to 250 lb
Why Riders Choose The 8'9" RIVER MKII
Everything the 9-7 does, in a smaller board. Attain upstream to play spots, surf it, run it, creek it, paddle expeditions on it — in a board that's 10" shorter and 2 lb lighter than the 9-7. The 35" width and 6" thickness keep it stable and floating high over river features.
Quick in tight water. The short waterline spins faster on a wave and fits lines a longer board has to work around — creeks, boulder gardens, and small play spots. The X-Ultra Grip deck pad and the contoured tail pad hold your stance through the rear-foot moves those places ask for: bottom turns, tail drops, and submerged tail pivot turns.
River construction, river warranty. The ULTRA RIVER core construction with X11 reinforcement layers in key areas is ERS's build for the water that punishes boards hardest — and it's backed by a 48-month warranty.
Built For Years Of Real Use
Rocks, shallow landings, and repeated impacts are just part of river paddling, and the MKII is built for them: ULTRA RIVER core with X11 reinforcement in the areas that take the most wear, at a board weight of just 19 lb. High-grade stainless steel D-rings at the nose, tail, and forward deck take a quick-release leash, tow line, or expedition tie-downs.
The Fin System
The LAKE RIVER COAST™ (LRC) Fin System on the RIVER MKII is a river-specific setup: two short US center fins (4.5" and 3") and two sets of two side click fins (4.5" and 1"), all packed in a padded ERS fin and accessories bag. The short fins suit shallow moving water, and the tuned toe-in angle preserves control; the center fin box accepts any US Fin Box-compatible fin plus FCS Connect™ tool-less center fins if you want to run something else for deeper water.
Full Specs
| Length | 8'9" |
| Width | 35" |
| Thickness | 6" |
| Board weight | 19 lb |
| Rider weight range | Up to 250 lb |
| Construction | ERS ULTRA RIVER Core Construction (X11 reinforcement) |
| Fin system | LAKE RIVER COAST™ (LRC) — two US center fins (4.5", 3") + two sets of two side click fins (4.5", 1"); US Fin Box + FCS Connect™ compatible |
| Deck pad | X-Ultra Grip texture with contoured tail pad |
| Included | Deluxe rolling backpack, high-pressure double-action pump, padded fin/accessories bag, 48-month warranty |
| Recommended use | Whitewater: river surfing, running rapids, attaining upstream, creeking, river expeditions |
Safety note for whitewater use
A standard ankle leash is not recommended for whitewater paddling. Use a quick-release leash, wear a helmet, and wear an inherently buoyant life jacket — all are important safety equipment in moving river water.
Inflation
The ERS 12VDC 20PSI Electrical Pump inflates this board to 15PSI in approximately 11 minutes. The included double-action manual pump inflates on both the downstroke and upstroke, cutting inflation time and effort roughly in half.
Choosing Between The 8-9 And The 9-7
Both sizes share the same construction, fin setup, deck pad, and warranty — the choice is about length and capacity. The 8-9 supports riders up to 250 lb and is quicker to spin on a wave, easier in tight creeks, and easier to carry. The 9-7 supports riders up to 290 lb and carries more length for momentum on attainment moves, bigger water, and loaded expedition paddling. Lighter paddlers and wave-focused riders tend toward the 8-9; heavier paddlers and those who run bigger stretches or carry gear tend toward the 9-7. Call the number below and we'll help you match the size to your river.
What's Included
Every 8'9" RIVER MKII ships with a deluxe rolling backpack, a high-pressure double-action pump, the padded fin and accessories bag with all included fins, and a 48-month warranty.
Contact a paddling expert on 877-777-1769 for our best package deal price and our review of the pros and cons of the Earth River SUP RIVER Series.
Related Reading:
- How to Choose a SUP Board for Whitewater and River Surfing
- When Should You Consider Buying A 6-Inch Thick Inflatable SUP?
- Why Buy From Pumped Up SUP?
- Which Earth River SUP Board Should I Buy?