The Sea to Summit Ultra Flex Bootie is a whitewater-specific shoe perfect for jamming into a low-volume kayak or swimming. The Velcro strap wraps around the heel, helping keep them securely in place, and the sock-like fit provides excellent flexibility. These water shoes stick well on hard surfaces but are too minimalist for longer hikes than some water shoe competition. The neoprene material can keep your feet warm and comfortable when wet. While these are great kayak-specific shoes, they don't function well on related dry land activities.Editor's Note: This water shoe gear review was updated on February 23, 2022, with new sections to help you make a buying decision suitable for your needs.
Sea to Summit Ultra Flex Booties Review
Cons: Not versatile, lack in support and protection for rough terrain
Manufacturer: Sea to Summit
Compare to Similar Products
Sea to Summit Ultra Flex Booties
|Price||$45 List||$130 List|
$43.94 at Amazon
|$63.71 at Backcountry|
Compare at 2 sellers
$129.95 at REI
|$37.46 at Backcountry|
|Pros||Very sensitive, good traction, secure for swimming||Exceptional comfort, great traction on wet surfaces, sensitive underfoot, drains well||Top-notch traction, flexible, snug fit||Versatile, light-weight, comfortable with a barefoot design, great for hiking on soft surfaces, good drainage||Durable, good traction on hard surfaces, fits well in a kayak|
|Cons||Not versatile, lack in support and protection for rough terrain||Sizing seems to run small, shows slight signs of wear||Lack in durability, not warm||Not warm without layers, not as durable as other models||Lack arch support and cushion, hard to wear with extra layers, lack versatility|
|Bottom Line||Great little booties that excellent in sensitivity and flexibility but lack in versatility and support||These shoes are comfortable and function-focused, sacrificing nothing for traction and versatility||This model remains the quintessential kayaking shoe with incredible flexibility and traction||A low-cut water shoe with a barefoot design, this model is versatile, showing great performance in and out of the water||A great low-volume bootie useful for a wide range of water-sports and at an affordable price|
|Rating Categories||Sea to Summit Ultra...||Chaco Torrent Pro -...||Astral Loyak - Women's||Xero Aqua X Sport -...||NRS Kicker Remix -...|
|Specs||Sea to Summit Ultra...||Chaco Torrent Pro -...||Astral Loyak - Women's||Xero Aqua X Sport -...||NRS Kicker Remix -...|
|Measured Weight (in lbs per pair, size US Women 8)||0.56 lbs||1.08 lbs||0.87 lbs||0.72 lbs||1.65 lbs|
|Drainage Features||None||Quick drying drainage||Outsole is draining||Mesh on upper, toe guard drainage holes||None|
|Footwear Closure||Velcro strap||Elastic quick laces||Laces||Laces||Drawcord with barrel lock adjustment|
|Upper Materials||3mm neoprene||Knitted polyester upper||Hydrophobic Canvas||Synthetic mesh, polyurethane||3 mm neoprene|
|Removeable Insole?||No removable insole||No removable insole||Removable insole||Removeable insole||No removable insole|
|Midsole||Rubber||Women's-specific LUVSEAT EVR midsole||7mm thick, 45C closed cell EVA foam||Non-absorbent tongue||Rubber|
|Outsole||Rubber||Non-marking ChacoGrip Plus rubber compound, self draining Flexi-grip||Flexi-grip, G15 (Astral tech)||FeelTrue rubber, 3.5mm dual chevron lugs||Rubber|
Our Analysis and Test Results
The Ultra Flex is a classic neoprene bootie featuring 3mm neoprene and a sticky rubber outsole. They weigh just above half a pound for a US women's size eight and fold down small for packing.
The Ultra Flex fits around the foot like a sock, kept secure by a velcro strap that wraps around the heel. While other shoes tested were likely to come off in a swim, we felt sure these weren't going anywhere.
The neoprene keeps your feet warm in cold water. But given its snug fit, anything more than a pair of wool socks was too thick to wear underneath. The Ultra Flex is the closest thing to sticky bare feet you'll find. Thus, walking on rough terrain is uncomfortable and potentially hazardous. On a boat and in the water, though, is where these shoes are comfiest.
The rubber outsole provides great traction on wet rocks, logs, and navigating a wet raft. This ability is aided by its flexibility, enabling your foot to follow the natural curvature of the surface.
The Ultra Flex essentially lacks lugs entirely, making them less than ideal for slick soft surfaces like a muddy trail or sandy hike. We found our arches and Achilles straining on these surfaces. That said, these shoes are purely for on-the-water activity.
The Ultra Flex isn't meant to be used across a wide variety of activities. It functions well as a boating-specific shoe and is comfortable and warm for full days on the water. It works well as a boating or swimming shoe, but you'd be unlikely to find us wearing it on a hike given its lack of durability and foot protection.
The neoprene materials provide excellent insulation when wet. Yet this is only up to the ankle, as adding warm layers was difficult.
We barely fit a dry-suited foot into it; a wool sock was as thick of material as the stretchy neoprene would accept. For truly frigid days, the Ultra Flex doesn't have enough layering capability. For more mid to higher temperatures, the Ultra Flex fits the bill.
The neoprene is glued to two pieces of rubber: the outsole and a smooth reinforcer between the two. The velcro strap seems a bit flimsy, but then again, you're unlikely to be yarding on the strap as much as you might with other shoes.
The neoprene is relatively thin, so it's subject to punctures or abrasions. For short walks up to the surf wave and takeout and promptly into a kayak, the Ultra Flex is fine. For navigating rougher terrain, the shoes will be worn down much more quickly than heftier shoes.
The Ultra Flex Bootie is the most sensitive shoe we tested. With no insole and a thin outside, you'll feel every bump and inconsistency. These shoes are ideal for swimming and playboating, given their low profile and neoprene construction, but are almost too sensitive for walking on land unless you're used to being barefoot entirely.
Should You Buy the Sea to Summit Ultra Flex Bootie?
The Sea to Summit Ultra Flex Bootie thrives as a boating-specific shoe but lacks function in other areas. The 3mm neoprene keeps your feet warm in cold water but is challenging to pair with socks or a drysuit. It's made to be flexible, sensitive, and low-profile, and for this, it excels. While you wouldn't want these shoes if you plan on doing long portages or scouts, it will do the job of scaling a boat ramp at the put-in and take-out. For the playboater or swimmer, these shoes are a great value. It provides decent warmth and traction for navigating short hikes or portages. They lack durability, but you won't break the bank just getting another pair if you put a hole in the neoprene.
What Other Water Shoes Should You Consider?
A similarly priced and higher performing shoe is the NRS Kicker Remix - Women's. This neoprene bootie is better for a wider variety of activities than the Sea. It also offers better warmth and durability, and if you find it on sale, you'll even save some money. If you need something with better traction or even more versatility, we love the Chaco Torrent Pro. This impressive shoe is comfortable warm and offers good sensitivity, but the performance comes at a higher price.
— Monica Nigon
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