Light, packable shell for changing conditions
Image: official product image from rab.equipment
Is the Rab Phantom Mountain Waterproof Jacket good for ultrarunning?
Mostly. The Rab Phantom Mountain Waterproof Jacket is a good ultrarunning pack layer for wind, showers and changeable conditions: it weighs 201 to 227g, packs into its hood and offers useful pockets. Its breathable 2.5-layer shell can feel clammy during hard efforts, and reviewers caution against relying on it in prolonged heavy rain.
Key facts
| Category | Waterproof jackets |
|---|---|
| Release | On sale from spring 2026 |
| Price | £160 RRP; one source lists it at £143.99. Also listed at $225. |
| Key specs |
|
| Best for | Ultrarunners and fast hikers wanting a light, packable shell for wind, showers and mixed conditions rather than prolonged heavy rain. |
| Consensus score | 8.5 out of 10 |
What is the Phantom Mountain?
The Rab Phantom Mountain Waterproof Jacket is a lightweight, feature-rich shell for running and fast hiking. Its 30D, 2.5-layer Pertex Shield Diamond Fuse fabric has a 20,000mm hydrostatic head and a stated MVTR of 20,000g/m²/24hrs. Product details put its weight at 201 to 227g, depending on source and size. Reviews from Live for the Outdoors and The Great Outdoors describe a soft, quiet fabric, while the adjustable hood, two hand pockets and pack-into-hood design make it more practical than a bare emergency layer.
How does it perform on ultras?
At 201 to 227g, the Phantom Mountain is easy to carry as a changeable-weather layer, and reviewers praise its breathability, wind protection and comfort on the move. One review reports staying dry through a couple of hours of torrential rain, but the wider verdict is more cautious: prolonged heavy rain can overwhelm the shell, and wet fabric may cling to bare arms. During sustained hard efforts, moisture can also build, particularly in humid conditions. It suits showers and mixed forecasts better than an ultra with relentless rain expected.
Who should buy this jacket?
The Rab Phantom Mountain Waterproof Jacket suits ultrarunners and fast hikers who want a packable shell for wind, showers and uncertain conditions, with pockets and an adjustable hood for regular use. Its 30D fabric offers a reassuring balance of low weight and durability, though the jacket is heavier than the standard Rab Phantom. Choose another option if dependable protection through prolonged heavy rain is your priority. Reviewers also note that sleeves can feel very long and cuff adjustment is limited, so checking the fit before a long outing is sensible.
What reviewers agree on
Strengths
- Lightweight and packs into its hood
- Breathable, soft and relatively quiet fabric
- Useful hand pockets and adjustable hood
- Durable fabric for a lightweight shell
- Effective wind protection and capable in showers
Weaknesses
- Not intended for prolonged heavy rain
- Can feel clammy or stick to bare arms in sustained wet conditions
- Heavier than the standard Rab Phantom
- Some reviewers found the sleeves very long, with limited cuff adjustment
Frequently asked questions
How does the Rab Phantom Mountain jacket fit?
It has a regular fit, with a stated 75cm centre-back length in size M. Reviewers found that the sleeves can be very long and that cuff adjustment is limited. If sleeve length or securing cuffs matters to you, try it on with your running layers before relying on it for an ultra.
Is the Rab Phantom Mountain durable and waterproof?
Its 30D Pertex Shield Diamond Fuse fabric offers a durability-minded balance for a lightweight shell, with a 20,000mm hydrostatic head. Reviewers found it capable in showers and reported one outing of a couple of hours in torrential rain, but caution that prolonged heavy rain can overwhelm it.
How does it compare with the standard Rab Phantom?
The Phantom Mountain is heavier than the standard Rab Phantom, weighing 201 to 227g depending on source and size. In return, it has a more substantial feature set, including two hand pockets, an adjustable hood and articulated sleeves. The available reviews do not provide a weight figure for the standard model.
Sources behind this review
How this review works: the consensus score of 8.5 out of 10 condenses the verdicts of the independent reviews and lab tests listed above, compiled by endurance coach Paul Forrest. Prices and specifications are those quoted by reviewers at the time of testing and may have changed.
Training for an ultra? See endurance coaching with Paul Forrest.
