Thurso Surf Expedition 138 iSUP Review – a Light Touring/All-Around Crossover | 2025

Thurso Surf Expedition 138 iSUP: Overview

I am often asked to help folks buy a paddle board that is both a comfortable all-around to learn with, but can go a little faster and won’t get outgrown quickly. In the past it’s been hard to really have a single board option that meets all of these requirements.

But, the Thurso Surf Expedition 138 is now part of a growing number of iSUPs that I’m referring to as “crossover” paddle boards that truly blend and blur the line between all-around and touring.

With a new 4.7” thick version of the Expedition 138 available and both the 6” and 4.7” options getting a bit wider, Thurso has bridged the gap and done so at a price that is beginner friendly. In this review we’ll be focusing primarily on the 4.7” Expedition 138, but will highlight the differences with the 6” version throughout.

— Thurso Surf Expedition 138 Ratings and Review Summary —

Thurso Expedition 138 iSUP Review – Construction and Durability

Thurso Surf is not a company that sits back and says “that’s good enough.” Instead each generation focuses on improving the quality and performance of their boards with the latest material innovations.

The new generation of the Expedition 138 is made with the latest technology in inflatable stand up paddle boarding. Inside the Expedition is a new cross-woven core. This double-wall fabric material uses woven (rather than knitted) fabric layers connected with thousands of drop stitch yarns in an X pattern (rather than a V) to reduce weight, reduce stretch and flex, keep the board rigid and flat when inflated, and now makes it available in both a standard 6” thickness for more capacity and rigidity or a 4.7” version for more stability and connected feeling to the water.

The outer shell of the board is made with a reinforced layer of PVC material that is mechanically bonded to the inner core with heat and pressure. This Fusion PVC material is lighter and stiffer than traditional hand-glued layups. It also helps eliminate potential issues of glue delamination over time.

The top and bottom of the board are joined together with a heat-welded inner seam. Like the Fusion PVC shell, welding mechanically bonds the rail layer with heat and pressure to the deck and hull to prevent glue and material softening and stretching. This makes the rail more durable and heat-resistant than hand-glued constructions. This inner seam is then protected by another layer of reinforced PVC material wrapped around the rail of the board, and another, thin, band of PVC is adhered to the top and bottom of the rail for even greater durability.

When it’s all put together with the deck pad, fittings, and on-board accessories, the new Thurso Expedition 138 has a maximum inflation pressure of 20 PSI and weighs just 20.8 pounds. The 6” version weighs just about a pound more.

In our bend static bend test we inflated the Expedition 138 (4.7”) to its maximum 20 PSI and loaded it with 170 pounds of weight in the standing area. Traditionally, thinner boards tend to bend more than thicker boards. However, the Expedition 138-4.7” did very well with just 1.62” of bend – right at our total running average for all iSUPs, regardless of thickness. That’s also slightly better than average for just the 4.7” iSUPs we’ve tested.

Our bend test lets us do some direct comparison between boards, but what really matters is how a board feels out on the water.

While standing and paddling normally on the Expedition 138-4.7” I didn’t notice any real flex in the board. If I went looking for it while paddling, I could feel some flex, but not much. However, when walking around on the deck I could feel a bit more flex, and could really feel it bending when paddling hard during a sprint test. Bouncing on the board created significant flex in the board, but when I stopped it settled down very smoothly and quickly.

The 6” version of the Expedition 138 has less flex on the water. At 225 pounds I would recommend for myself that I paddle on the 6” version for the additional stiffness, and the same goes for any paddlers over 180-ish pounds. But that’s also going to depend on what you are looking for. I still really like the overall feel of the 4.7” version even though it does have a bit more flex for me as a heavier paddler.

At the end of the day I’ve been very impressed with Thurso’s new construction. I think there is some room for improvement on rigidity with their 4.7” boards through various stringers and other stiffening measures, but having a 6” version for heavier paddlers also solves that problem on its own.

Thurso Expedition 138 – 4.7” Specifications

Specifications

Thurso Expedition 138 – 6” Specifications

	Dimensions
	Length	12’ 6”
	Width	30.5”
	Thickness	6”
	Weight
	Max Capacity	330 lb
	Board Weight	24 lb
	Kit Weight	lb
	Buying Info
	List Price	$549.00
	Warranty Period	2 Years
	Returns Period	30 Days

Features, Accessories and Versatility

The Expedition 138 shares all the same features and accessories as the larger 12’6” Expedition 150, including plenty of cargo space, cooler and kayak seat compatibility, built-in action mounts, and more.

In addition to offering the Expedition 138 in two different thicknesses, Thurso is also offering their new boards as either a “board-only” option, or a full-package kit. The 4.7” version is only available in the “board-only” configuration. With the “Board Only” option you get:

• Thurso Expedition 138 (4.7” or 6”) iSUP
• Compression strap
• Small accessory bag
• Coiled Leash
• 9” touring fin
• Basic repair kit

With the “Full Package” option for the 6” version you get everything above plus:

• Wheeled SUP backpack
• Electric Pump with internal battery
• Three-piece carbon/nylon hybrid paddle

While the “Board Only” option does not include a bag, pump, or paddle, you can still choose to bundle these items with the board. They are discounted, though not quite as heavily as when selecting the full package.

Thurso Expedition 138 iSUP Review – Paddle

The Expedition 138 comes with Thurso Surf’s standard carbon fiber/nylon adjustable 3-piece paddle when you select the Full Package option. It’s an excellent balance of size, weight and comfort. Thurso Surf also offers a full carbon fiber paddle blade that is also well worth the upgrade.

The adjustable 3-piece carbon fiber/nylon paddle balances weight, stiffness, power, and comfort well. The medium-large carbon/nylon blade isn’t too heavy to throw off the balance of the lightweight carbon fiber shaft. It has a traditional low-aspect/teardrop shape and both a slight scoop and rake angle. The scoop helps hold better in the water and counteract flex from the nylon blade, while the rake angle helps keep the paddle vertical for a longer period of time during your stroke – both of which help increase the power you can generate from a single paddle stroke.

The handle section of the paddle is a little different than most kit paddles with its T-grip handle. T-grips allow you to grip the handle a little tighter than a standard palm grip, but they also give you tactile feedback on how your blade is oriented in the water. This T-grip also has a rubberized coating for even better grip when wet, but it’s not so textured that it rubs your hands while paddling.

Thurso also makes a fully carbon fiber blade that is compatible with their current paddle shafts. The Carbon Elite blade is a touch smaller than the nylon hybrid blade and has a narrower outline. Additionally the blade face loses the scoop shape, but gains two dihedral lines. These lines both help direct water off the blade to reduce fluttering and they create a pocket in the blad face to increase the paddle’s hold in the water.

While most brands that offer carbon fiber upgrades like this require you to purchase an entirely new paddle, Thurso Surf offers their Carbon Elite blade as a stand-alone product at a significantly reduced price compared to a new carbon fiber paddle. The Carbon Elite blade upgrade is absolutely worth getting to pair with your Expedition 138. The increase in power and decrease in weight is very noticeable and welcome for longer days on the water or paddling at faster cadences and speeds.

Thurso Expedition 138 iSUP Review – Stability

The Expedition 138 has changed pretty significantly from the previous version. The new outline and shape makes it more stable than before, but may still be limiting for larger beginner paddlers.

Width plays a very important role in paddle board stability. Previously, the Expedition 138 was quite narrow at just 28.5” wide. However, this year, Thurso increased the width to a specified 31”, though ours measured 30.5”. At this size that last half inch can make a difference, especially in rougher conditions.

However, height off the water (aka board thickness) also makes a difference in stability. A lower center of gravity can improve your stability as well.

What I’m trying to get at is even though this is a “smaller” board, it actually feels quite stable for its size. I found standing and paddling on the board to be comfortable in calm and light conditions, though I did feel a little bit of twitchiness as wind and chop increased.

I did find it to be a little tricky to hold this smaller board on its edge, and I did feel it “catching” slightly as I rocked it side to side. But, again, during normal paddling, I didn’t notice these effects very frequently.

In my case, at 225 pounds, the Expedition 138-4.7” is a little small for me. Though a thinner board can increase stability for some paddlers, the slightly lower rigidity can actually decrease stability for heavier paddlers. The 6” version solves both of these issues for me as an advanced paddler. The extra rigidity and higher volume helps keep the board feeling a little more stable for me and eliminates that slight twitch feeling.

For a true beginner, I would recommend a maximum rider weight of around 150 pounds for the 4.7” version and 180 pounds for the 6” version. But, for those novice paddlers looking for a board that will give them a slightly faster and sportier feel, you could add 20-30 pounds to each of those recommendations.

If you do want a more consistently stable SUP to learn on, and aren’t as interested (for now) in going farther and faster more efficiently, then I would recommend checking out the Waterwalker 132. It is a full 32” wide, has a more stable shape overall, and is also available in a 4.7” and 6” version.

Thurso Expedition 138 iSUP Review – Speed

As a crossover SUP, the Expedition 138 offers a little more speed than your typical all-around, but not quite as much as a more traditional touring board.

The narrow size and gently-tapered outline of the Expedition 138 keep it gliding smoothly and efficiently on the water. It does offer a little more speed than your typical all-around, but it will also depend on your size and whether you are on the 4.7” or 6” version.

When paddling the 4.7” version of the Expedition 138 in our speed testing I could feel noticeable bend and flex that was likely reducing its highest speeds. At a sustained sprint of 75 strokes per minute, and using the Thurso Carbon Elite paddle blade, I averaged 5.1 MPH. On a full-on sprint I was able to reach a maximum of 5.5 MPH.

However, on the 6” version of the Expedition 138, those speeds do increase for me by about 0.2 MPH as the board bends less during this high-energy paddling.

At a casual cruising speed, things calm down significantly, and there is very little flex in the 4.7” Expedition 138 for me. At 25 strokes per minute – or slow enough to take a slight pause between paddle strokes – the Expedition 138 cruised along at 3.7 MPH with no issues. Results are about the same for the 6” version. At that cruising speed, I was able to glide for 21 feet on average with a single paddle stroke before slowing down. That’s a gliding ratio of 1.8 board-lengths per stroke.

Overall, this gives the Expedition 138 a bit of a speed boost compared to your standard all-around for cruising speed and efficiency, though sprinting speeds aren’t that much higher. On the flip side, it’s also a little slower than traditional touring SUPs that are longer and a little narrower

Thurso Expedition 138 iSUP Review – Maneuverability and Tracking

The Expedition 138 offers a really interesting balance of maneuverability and tracking that keep it agile, but also easy to paddle straight.

The shorter length of the Expedition 138 does a great job of improving maneuverability compared to other touring iSUPs. Using a forward sweep stroke (starting at the nose then sweeping out and back to the tail) from a standstill, the Expedition 138 can execute a full 360° turn in flat water in just 5.5 strokes on average. This is an incredibly small turning radius for a touring board, and is even on the smaller side for many all-around boards. In addition to the shorter length, the Expedition 138 also has a single fin box. While this test was done using the included 9” touring fin, the lack of other fins does help it turn faster.

When using reverse sweep strokes, the Expedition 138 turns even quicker, completing the same 360° turn in just 3.5 strokes. While using reverse strokes to turn your board does give you a tighter turning radius, it also stops any forward momentum you have, so it’s best to use these strokes only when stopped or at very low speeds, so their use while paddling is a little limited.

Lastly, turning using more advanced techniques like bow-draws and pivot turns is much quicker, however the smaller size of the Expedition 138 (especially the 4.7” version) does make pivot turning significantly more challenging as the stability is greatly reduced over the tail. The raised kick pad on the tail is set a bit too far back to really offer any improvement in traction and control, unfortunately.

Touring paddleboards are known for their efficiency in a straight line, partly due to their excellent ability to paddle straight with very little corrective input (also known as tracking). The Expedition 138 likewise offers great tracking ability, however not quite to the level that we’ve seen with more traditional size touring boards like the Expedition 150.

While cruising around the Expedition 138 was easy to keep on course and needed very little steering input. In our 10-stroke tracking test, the Expedition 138 did very well, averaging only a 12° course deviation while paddling 10 strokes on one side. This puts it squarely in between most all-around and most touring iSUPs.

The Expedition 138 comes with a single 9” rigid touring fin to match its single US Fin box. The US Fin box is a standard system that’s been around for decades and has hundreds of different compatible fins from dozens of brands – so if you need to change this fin out for another one to better suit your style of paddling, it’s very easy to do.

The included fin also comes with several Kumano plastic inserts (the orange disc in the photo above) that allow you to install the fin securely without any tools. This is a great time (and headache) saver compared to using fin bolts and nuts. I’m a huge fan of this system.

The 9” touring fin is well matched to the Expedition 138. On touring boards I do typically prefer to have just a single fin as it can reduce drag and improve efficiency. The lack of the side fins does improve the Expedition 138’s agility compared to the Waterwalker 132 but doesn’t lose any tracking performance.

There’s no noticeable difference in maneuverability or tracking between the 4.7” and 6” versions of the Expedition 138.

Thurso Expedition 138 iSUP Review – Warranty and Customer Support

The Expedition 138 is covered by Thurso Surf’s 2-year warranty against any manufacturing or material issues. They also offer a 30 day return policy. These are fairly standard length warranty and return periods and Thurso Surf has been very responsive to customers with questions or concerns. You can reach Thurso Surf via their online form, email or social media.

Thurso Expedition 138 iSUP Review – Final Thoughts

The Thurso Surf Expedition 138 is a great crossover all-around and touring board for smaller beginners or for intermediate and advanced paddlers who want more of a sporty feel. It’s agile, but easy to paddle straight. It offers good stability for most paddlers, but can also pick up some speed when you want.

The ability to select a 4.7” or 6” version of a board is fantastic, as is the option to get a full kit or customize one for yourself.

I really like paddling the Thurso Expedition 138 – even if the 4.7” version is a little small for me – but I will have trouble deciding if it goes in the Best All Around SUPs list or Best Touring SUPs list (maybe I need a new crossover list!).