The products mentioned in this article are selected or reviewed independently by our journalists. When you buy through links on our site we may earn an affiliate commission, but this never influences our opinion.

Castelli Idro 2 jacket review

The perfect racer's rain jacket

Our rating 
4.5 out of 5 star rating 4.5
GBP £300.00 RRP | USD $260.00 | AUD $479.00
Black waterproof road cycling jacket with red trim from Castelli

Our review

Lightweight jacket offering pro-level rain protection
Pros: Waterproofing, breathability, race cut, packable
Cons: It doesn’t come cheap
Skip to view product specifications

Castelli’s Idro 2 uses the same fantastic fabric as Gore’s much acclaimed range of Shakedry waterproof jackets. Similarly, it delivers top-end, weather beating performance in a highly breathable, lightweight, small package that’s superbly waterproof.


So what’s different, you may ask? Castelli has designed the Idro 2 with the racer in mind and the result is a pared back, minimalist rain jacket that has all the essentials but does away with any unnecessary gimmicks. So, there are no pockets, extendable flaps, wrist adjusters or zip flaps.

The simple design results in the Idro 2 being super-lightweight and my size small tipped the scales at a mere 105g. It’s also one of the smallest packing fully waterproof jackets on the market and easily packs into a jersey pocket. It is so bijou and feathery that it’s more like a lightweight, emergency windproof jacket.

The Shakedry fabric is different to most in that it’s only a two-layer fabric. The outer layer acts as the waterproof membrane, so rain literally rolls off, and it doesn’t wet-out and is completely waterproof.

If water does sit on the jacket you can shake it off and it’s dry, hence the name. It sounds amazing, and really is, keeping the wet stuff out.

With this level of rain beating performance you might expect the breathability to suffer. Nothing could be further from the truth. This fabric has to be one of the best out there when it comes to stopping you from getting wet on the inside. Even when working hard, the breathability is nothing short of impressive.

The cut is fitted, making it ideal for the race whippet, so most of us mortals will probably need to size up. Being fitted not only makes it flap free but more efficient on the road.

The long drop-tail offers superb rear spray protection and stays perfectly in place thanks to the elasticated hem. There’s also plenty of arm coverage to seal well with whichever gloves you prefer to ride in.

The Idro 2’s frill-free nature and simplicity is executed well. The wrist cuffs use narrow bands of elastic to seal out the elements and worked a treat without being loose, or feeling overly tight or restrictive. The same can be said of the collar. It’s not overly tall but did its job well, too. There’s no zip garage either, but I never missed it.

Up front, the large-toothed YKK waterproof zip does a top job of keeping out the cold and wet. Castelli has added a simple pull tag extension and this makes life far easier, especially in gloves. There’s no draft flap, but it wasn’t an issue with the zip sealing so well.

The Idro 2 is finished with neat reflective logos and has contrasting red stripes that give it a racy look. All of this combines to make a truly great rain jacket that’s worthy of its price tag.


You may pay more for less, but it’s perfect for the racer who wants one of the best rain jackets available.

Product Specifications


Price AUD $479.00GBP £300.00USD $260.00
Weight 105g
Brand Castelli


Features Sizes: S, M, L, XL, XXL, XXXL
Colours: Black
Key features Waterproof, windproof and zip closure