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(The Gear Loop) - Nobody wants to carry a lot of weight, and camping gear adds up fast. A sleeping bag, mat, tent and cooking gear can easily tot up to more than your back will enjoy. 

This is where the ultralight tent comes in, and where the Sea to Summit Alto TR1 is positioned: a one-person, solo living quarters, although sensibly with a two-person model is available too. 


However, the TR1 offers a total weight of 2lbs, or around 1.2kg on this side of the pond. So how does it achieve this feat, and is it actually usable - unlike some weight-comparable ultralight racing tents? 

Sea to SummitSea to Summit Alto TR1 review photo 2
Our quick take

Broadly, we were impressed with the Sea to Summit Alto TR1. The build quality is excellent, the component parts are good quality, and the design is simple where it needs to be, ingenious where it doesn’t. The Sea to Summit Alto TR1 abounds with neat touches - especially the light bar, which is great fun - and the attention to detail shines through.

The big question for buyers is whether the slightly larger and heavier TR2 would be a more flexible choice, and whether the three-season rating of both (thanks to that mesh inner) will be sufficient for serious weather.

Sea to SummitSea to Summit Alto TR1 review photo 7

The pegs are an exception, but to be fair there’s many an excellent tent that has pegs that are either ludicrous titanium skewers (Terra Nova Laser, we’re looking at you) or unnecessarily heavy steel/alloy jobs to cut manufacturing costs. Either way, a new set here is no major investment.

Otherwise, this is a top-notch tent that delivers lightness and quality in a compact package - brilliant stuff. 

Sea to Summit Alto TR1 review: a super light solo tent for lightning fast adventures

Sea to Summit Alto TR1

4.5 stars - The Gear Loop recommended
  • Excellent build quality
  • Simple but clever design
  • Packs down easily
  • Only 3 Season
  • Two-man version is more flexible
  • Pegs not the greatest


In the Loop

Everything you need to know about the Sea to Summit Alto TR1 tent

  • Floor area: 19.5 sq. ft.
  • Floor dimensions: 84.5 x 42 x 24 in
  • Fly & footprint pitch weight: 1lb 11.3oz
  • Minimum trail weight: 2 lbs. 1 oz
  • Packed size: 4 x 18 in
  • Packed weight: 2lbs. 7 oz
  • Peak height: 42.5 in
  • Pole diameter: 8.7 and 9.5mm
  • Vestibule area: 7.5 sq ft


As you might expect, there’s quite a bit of design ingenuity involved in making a tent this light, and Sea to Summit has really gone to town here. The overall system will be familiar to any tent-botherer - a mesh inner and groundsheet, a single but multi-branched pole system and an outer flysheet. 

Sea to SummitSea to Summit Alto TR1 review photo 5

These three elements mean that set-up is pretty idiot-proof, as well as being quick and efficient, but more on that later. 

The pole system features Sea to Summit's proprietary Tension Ridge Pole Technology, which essentially involves the top lateral pole angling up rather than down. This creates extra space within the tent, especially around the top part, which is often a little snug otherwise. 

A pair of curved foot-end poles create maximum roominess at the other end too, creating a surprisingly spacious living area - big enough for two at a squeeze, and palatial for one. The porch area is less roomy, but perfectly adequate for one, plenty of space for boots and an emptied rucksack, although cooking in poor weather would be a bit of a challenge.

Sea to SummitSea to Summit Alto TR1 review photo 3

One feature that really stands out is arguably one of the silliest, but certainly most ingenious - the light-bar. This is a simple opaque panel on the side of the pole bag, which when popper-attached to the apex of the inner can have a head torch stuffed inside as a light diffuser. 

The inner and flysheet stuff sacks similarly connect to the lower walls as gear storage pockets. It’s a simple idea, but one we love - transforming those stuff sacks and pole bags into multi-purpose tools, useful both in transit and when pitched up for the night. 


Thanks to the modularity of the design, there are several different configurations that you can pitch the Sea to Summit Alto TR1 in. 

Mark MayneSea to Summit Alto TR1 review photo 9

Most obviously, you can pitch just the inner - say in fine weather - so you can stargaze through the mesh at night. 

In the UK, this is a high-risk and often sopping wet operation, but fortunately you can also do the opposite, and pitch the flysheet first - a handy trick if it’s chucking it down - then assemble the inner under cover, keeping it slightly drier.

The DAC NSL pole-set is of top-notch quality, and comes with a repair sleeve, fortunate, as getting the poles set into their aluminium feet does take a little force. 

Mark MayneSea to Summit Alto TR1 review photo 10

The attachment system is also an ingenious take on existing systems - the rear hoop and front nose of the poles slip into holes in small aluminium plates linked to the inner, anchoring everything neatly. 

The Flysheet then clips - using C-shaped alloy discs - into the same points, ensuring that everything is tensioned and lined up correctly. Sea to Summit's marketing states that the aluminium plates are in fact a 'Quick Connect Foot' which is a ‘beautifully designed, machined aluminium clip’, which is no idle hyperbole, they really are smoothly finished, and engineered to last. 

Meanwhile, the flysheet’s Tension Ridge Pole Technology is encapsulated in a couple of highly-robust, thick rubber grommets which trap the ends of the tension pole, keeping everything nailed down even when pitching in a reasonable breeze. 

Mark MayneSea to Summit Alto TR1 review photo 11

Pegs and accessories

The pegs are - weirdly - the worst and best part of the tent. At first glance the triangular/Y- section alloy units with neat serrations to trap guylines look excellent - strong but light, with neat cord loops to help extraction. 

However, the tops of the pegs are left slightly rounded, but open profile, making them exceedingly sharp. This is initially obvious when trying to push them into the compacted earth, a problem easily offset by using a handy stick to protect our palms. 

However, walking past the tent in flip-flops and cack-handedly standing on a peg results in a deep puncture wound in the foot - boots are mandatory here if you’re the type of person to trip on a guyline. 

Sea to SummitSea to Summit Alto TR1 review photo 6

This is a shame, as the pegs are otherwise excellent, and perform well through a windy night. A new set of less fierce pegs will be packed next time!   

Shockingly, we’ve been rain-free so far in testing the Sea to Summit Alto TR1, but the seam-taped Silicone / Polyether Polyurethane coated 15D nylon rain fly looks very much up to the job, and although (inevitably) lightweight, it’s not as gossamer-thin as some ultralight tents we’ve used. 

Similarly, the deep 15D nylon tub floor is rated to 1200mm hydrostatic head, and although it’s best used with a footprint on rougher surfaces, it’s OK on the grassy terrain we’ve tested so far, and less lightweight than some. 

Sea to SummitSea to Summit Alto TR1 review photo 8

Like many manufacturers, Sea to Summit recommends using a bespoke footprint to protect the tent floor on rougher ground, which is worth considering, even if you opt for a cheaper option like a tarpaulin or similar.  

Even in good conditions, condensation can be a problem, and the Sea to Summit Alto TR1 has a robust solution baked in. As well as the highly-breathable mesh inner, the flysheet has a near-full-width vent concealed in the apex, which can be zipped open, or closed to suit conditions. A couple of stiffened prongs keep this tensioned nicely and open when needed, and it works very well in practice, as well as theory. 

As mentioned, space in the Sea to Summit Alto TR1 is decent, both in floorspace and more usable head-and-shoulder space as promised by the Tension Ridge arrangement. We even managed to fit a full-size single mattress-style camping mat into it, so there’s masses of room for a standard ultralight mummy-style variant. 

Mark MayneSea to Summit Alto TR1 review photo 13

At a shade over a kilo, this is genuinely lightweight too, easily carry-able for long distances if needs be, and in context, very good value for its weight. A good-quality bivvy bag weighs in between 400 and 1,000-odd grams, and that’s a far more spartan environment to dwell in than the Sea to Summit Alto TR1, which is entirely comfortable for the solo traveller.   


To recap

With its excellent build quality, clever features and seriously light packed weight, this is a fantastic tent for thru-hiking or lightning fast treks across big distances. We were also pleasantly surprised at how much living space it offered given the footprint and how well engineered it felt at this price.

Writing by Mark Mayne. Editing by Leon Poultney.