Real Review: Stern Bag for the 2022-up Kawasaki Ultra 310 JetSkis

Kawasaki never really “led the charge” when it came to accessories for its JetSki lineup, especially when compared to Sea-Doo or Yamaha. For 2022, however, Kawasaki stepped up their game and launched a full line of new accessories designed accompany the latest generation of Kawasaki Ultra 310 Jet Skis

The 7-gallon Stern Bag accessory ($309.95) is compatible with all three Ultra 310 trims, and can be installed whether or not your ski features an Ultra Deck. The bag is made of soft yet rigid material, has a “flow-through” design with a mesh-like bottom that allows the bag to “breathe,” and seamlessly accommodates Kawasaki’s optional 1.3-gallon Soft Cooler ($110.95).

Upon unboxing the Stern Bag, the quality of the accessory was immediately apparent. The bag has a satin sheen, with a soft yet rigid texture. Dual zippers- protected from the elements by a canvas sheathe- provide easy access to the bag’s main pocket. Inside, the bag features a mesh-lined bottom, reinforced with a rigid plastic stiffener.

Since the Ultra 310s feature a small storage pocket on the stern, just below the passenger seat, the Stern Bag features a zippered pass-through pocket inside so that this compartment and the ski/tow hook can still be accessed with the bag mounted to the ski.

The Ultra 310 has more than enough storage, but adding this bag to the rear allows you to easily access anchors, fishing gear, or drinks that might be too deep in your front compartment to conveniently reach while on the water. With the Ultra Deck, there is still room behind the Stern Bag to board the ski from the water or jump off the back.

The bag is flanked by a dual fishing rod holders- molded right into the sides. The holders are complete with adjustable nylon straps to securely lash your rods in place. The rods are held at about a 45 degree angle, and not straight up and down.

The optional 1.3 gallon Soft Cooler fits like a puzzle piece inside the Stern Bag- with room to spare for lines, anchors, supplies, or gear. Keep in mind that the Stern Bag is not waterproof nor does it claim to be. The bag’s design does allow its contents to dry out fairly quickly when stored, so that items in the bag don’t get moldy or musty.

The Soft Cooler has a durable canvas texture and features Kawasaki branding. It does provide decent insulation and does accommodate a 64 oz stainless water bottle and an ice pack pretty well. It would have been great if the Soft Cooler was included with the Stern Bag, as the $110.95 price tag seems pretty steep for something this small.

The plastic base of the Stern Bag serves as the primary mounting point, and is held securely to the rear of the ski via two plastic knobs and stainless-steel t-nuts. These t-nuts are installed in the Multi-Mount Rails embedded in the Ultra Deck. 310X models without the Ultra Deck feature pre-threaded pilot-holes for the purpose of installing this bag.

The primary mounting point on the plastic base of the Stern Bag does not require that any modifications be made to the ski. When it comes to the secondary mounting straps, however, Kawasaki’s factory installation instructions instruct installers to drill two 3/16ths holes on either side of their ski in order to mount the “Stayput knobs” that hold the bag’s upper straps in place.


While the video below does cover basics of the factory installation methods, this author had ZERO interest in drilling holes in his ski, so an alternative method utilizing industrial and water-resistant Velcro was devised. Speaking with other 310 owners, it seems that everyone is in agreement about the aversion to drilling holes in a brand new $20,000 JetSki.

Before advising others that this “Velcro Method” was a viable alternative, JD’s Waterworld took to the seas, and spent a few hours out on the water (in fairly rough conditions) testing the limits of the drill-less installation method.


The Stern Bag was loaded up with dock lines, 2 foam fenders, an extra pair of riding boots, a small Danforth anchor with line and chain, and the Kawasaki Soft Cooler filled with a few bottles of water and an ice pack.

Throughout the ride, the Stern Bag maintained its structural integrity, remaining attached to the ski at both the stern and upper Velco attachment points. While Velcro’s tensile strength is much less than a physical mounting-point secured by a 2” 3/6 stainless nut and bolt, the Velcro does provide the necessary tension to keep the upper straps secured to the ski when riding in moderate chop.

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JD Brussels

A true Florida native, JD bought his first boat before he was old enough to drive. You can usually find him tinkering on one of his many projects, tearing up the ocean on his Ultra 310, or spending time out on the boat with his wife and 3 kids.

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