When a company like Sigalsub announces its entry into the carbon fin sector, expectations are high, very high. The new Tsunami fins are designed to enter the mid-to-high range market, but with clear ambitions: to present themselves as a real alternative to current offerings, delivering an excellent balance between performance, comfort, and price.

We tested them extensively, both in the pool and in open water, and we can say with confidence: they’re not just beautiful, they’re functional down to the last detail.

A modern design, not just for looks

At first glance, the Tsunami fins impress with a clean yet distinctive design. The T700 carbon laminate features an orderly weave, glossy but not flashy. The blade’s profile is linear, with progressive curves, seamlessly integrated into the foot pocket thanks to a carefully engineered angle.

Handling the fins, you immediately notice a product that is both lightweight and robust, with a smooth, harmonious flex. The 100% carbon construction (no mixed fibers) allows for a responsive blade, capable of absorbing and returning energy very fluidly. The side rails are well-proportioned, avoiding energy loss during finning.

The new 250 foot pocket is clearly inspired by the design philosophy of the iconic C4 200 and 300 models: lightweight, efficient power transfer, and comfort are the key priorities.
It’s made from thermorubber with variable density and features a hybrid structure: soft on the instep to reduce pressure points, and stiffer on the sides where energy transfer is needed. The anatomical shape hugs the foot without constraining it, delivering a precise and responsive feel — ideal for both dynamic apnea and spearfishing.

During pool tests, the foot pocket felt very neutral in fit, with a smooth yet powerful energy transfer. It is fully compatible with carbon blades.

In the Water

I tested the Tsunami in a 25-meter pool, doing dynamic apnea drills and repeated sets. The blade response is immediate, especially during recovery: it doesn't drag the foot down, but rather supports the movement. During turns, it returns power without losing control — a quality often overlooked in stiffer models.

At sea, I tested them on dives down to 20 and 25 meters, using neutral buoyancy, during both ambush-style and active bottom spearfishing. The performance was exemplary: no vibrations, linear energy transmission. The descent is aided by a strong initial thrust, while on ascent, the Tsunami fins deliver a solid, uninterrupted kick that helps maintain good hydrodynamics even under effort.

A special mention goes to their versatility. I was able to operate in shallow water just as comfortably as on deeper dives, a trait that makes them perfect for divers alternating between indoor training and deep-sea fishing.

Advantages

Progressive thrust: excellent energy management, ideal for dynamic apnea and deep spearfishing

Comfort: well-designed blade/foot pocket angle reduces joint stress over long distances

Lightweight in water: do not cause fatigue, even during long ascents or surface swims

Full T700 carbon construction: top-notch quality, outstanding reactivity

Directional stability: very precise, with no lateral slipping, even during wide kicks

Limitations

Not for everyone: although accessible, carbon blades require care and a bit of attention to avoid damage

Competitively priced, but not entry-level: positioned in the mid-to-high range, aimed at demanding users