What it does
During sandstorm, Sand Veil gives the holder two effects: its evasion rises one stage (equivalent to every incoming move having its accuracy multiplied by ×0.8, a 20% miss chance), and it takes no chip damage from sand weather.
What that means numerically: a 90% accuracy move hitting a Sand Veil holder in sand has effective 72% accuracy. A 100% accuracy move drops to 80%. Over the course of a game that burns five or six attacks, roughly one would miss. That miss might be decisive or it might be irrelevant — Sand Veil gives no control over when it fires.
Sand Veil is only active during sandstorm. If the weather shifts or the sandstorm ends, both benefits disappear immediately. Building around it requires a reliable sand setter — Sand Stream via Tyranitar or Hippowdon, or a Sandstorm user on your team.
Who runs it
Sandaconda (76%) is the clear leader. Ground-type, so it doesn't take sand damage anyway, and it's exactly the kind of durable physical presence that benefits from a free evasion layer over many turns. Gliscor (17%) has Ground/Flying typing that already blanks a number of attack types — Sand Veil adds a probability layer on top of that natural durability. Stunfisk (30%) splits between Sand Veil and Static; in sand teams, Sand Veil is sometimes the better pick. Garchomp (6%) usually prefers Rough Skin, but Sand Veil is a real option. Heliolisk (4%) and Orthworm (0%) see lower adoption.
How to use it
Set up sandstorm, then keep your Sand Veil Pokémon in the field and let the evasion do its thing. There's no active input required. The more turns your Sand Veil holder survives, the more attack opportunities the opponent loses to the 20% miss chance.
Don't put the game on Sand Veil. When it misses for you at a critical moment, great. When it doesn't trigger all game, your team still needs to function on its own merits. Sand Veil is a bonus, not a plan.
Tips & strategy
Sand Veil is genuinely controversial competitively because it's entirely RNG. That's true — it offers no skill expression beyond choosing to use a Pokémon with the ability in a sand team. What it does offer is zero-cost passive defense: no item slot, no moveset slot, no training resource. A free 20% miss chance over the course of a game is statistically positive over many games, even if it's invisible in any single match.
In doubles, if both field Pokémon have Sand Veil, both benefit independently — the opponent's attacks against each one run the ×0.8 accuracy modifier separately. That's a non-trivial compounded miss rate against a sand-optimized lead pair.