What it does
Aqua Jet is a Water-type physical move: 40 base power, 100 accuracy, +1 priority, no secondary effect.
Its entire competitive value lives in the priority bracket, not the damage number. Anything using a standard (priority 0) move acts after Aqua Jet regardless of speed stat — the gap is completely irrelevant. This lets slow Water-type physical attackers move before they'd normally get a turn at all.
A concrete number to anchor this: Azumarill sits at roughly 132 max Speed in Champions (Lv50, 31 IVs, no Speed Stat Points, neutral nature). A Choice Scarf Iron Bundle hits around 230 Speed — under normal circumstances, Azumarill never acts before it. But after Belly Drum with Huge Power, Azumarill's Attack reaches the equivalent of a base-stat 300+ attacker. At that Attack level, Aqua Jet at 40 BP delivers enough real damage to clean any target already below ~40% HP — that's the kill window. Priority bought the turn; Huge Power supplied the punch.
Speed control in Champions doubles is constant: Choice Scarf, Tailwind, and Trick Room all appear on competitive ladders simultaneously. Aqua Jet sidesteps all three by operating outside the speed tier entirely — with one named exception in Trick Room (see Tips below).
Who runs it
Azumarill runs Aqua Jet on ~96% of sets — near-universal. The core trio is Huge Power + Belly Drum + Aqua Jet: Belly Drum pushes Attack to +6, priority lets the follow-up land before the opponent responds, and Sitrus Berry patches the 50% HP cost of Belly Drum so it can survive into the next turn. Stat Points go fully into Attack (capped at 32), typically with an Adamant nature. After Belly Drum, Aqua Jet at just 40 BP still OHKOs most targets that are below half HP — the modifier stack (×2 from Huge Power, ×6 from Belly Drum, ×1.5 from STAB) makes base power almost irrelevant.
Basculegion carries Aqua Jet on ~91% of sets alongside Last Respects. Adaptability bumps same-type STAB from 1.5× to 2.0×, which means Aqua Jet effectively hits at 80 base power equivalent on Basculegion specifically — half the value of Wave Crash but with a priority bracket attached. The division of labor is clean: Last Respects hits healthy targets (its power climbs as teammates faint), Aqua Jet closes targets already in chip range without burning a Last Respects action or PP on a kill that didn't need the firepower.
Quaquaval uses it on ~38% of sets as a defensive fallback. Quaquaval isn't slow, but when a Choice Scarf user is in play, Aqua Jet lets it still act first in situations it otherwise couldn't.
Beartic runs it on ~31% of sets. Under Swift Swim or Slush Rush weather, Beartic's Speed doubles and it doesn't need priority — but once weather ends and Speed reverts, Aqua Jet covers the gap.
How to use it
Doubles core sequence: Create a safe setup window through partner support — Fake Out to flinch a threat, or Rage Powder / Follow Me to redirect attacks — then fire Aqua Jet on the turn after setup to clean before opponents regroup.
Azumarill textbook turns: Turn 1, partner uses Fake Out on the biggest immediate threat, Azumarill uses Belly Drum. Turn 2, partner attacks the second target, Azumarill uses Aqua Jet at +6 Attack with priority — nearly anything weakened goes down. The entire framework is "Turn 1: safe setup, Turn 2: priority sweep." If Fake Out support isn't available (opponent has Inner Focus, or partner already used it), fall back to Protect first to probe for the safe Belly Drum turn.
Singles logic: The highest-value moment is the turn the opponent switches in. They send in a fresh Pokémon expecting to act first, Aqua Jet fires in the priority bracket before that switch-in can do anything — you've already removed HP before they respond. Basculegion typically leads with Last Respects or Wave Crash on full-HP targets, then closes with Aqua Jet on anything already in the 30–40% range where high-BP moves would be overkill for that action.
Priority collisions: Aqua Jet at +1 only beats priority 0 and below. Against Fake Out (+3), Extreme Speed (+2), or another Aqua Jet / Sucker Punch (+1), speed resolves within the bracket normally — the priority assumption breaks down. Build your turn prediction around this; don't treat Aqua Jet as a guaranteed first mover against aggressive priority users.
Tips & strategy
Common-mistake autopsy — using it on healthy targets: The most frequent beginner error is firing Aqua Jet at an opponent sitting above 60% HP because "it's Water STAB and I want to go first." At 40 BP, even with solid Attack investment, Aqua Jet deals significantly less damage than Liquidation (85 BP) or Wave Crash (120 BP). Against a target that isn't going to faint, you've just spent an action doing subpar damage instead of chunking them into the kill range where Aqua Jet would actually matter. The fix: use your high-power move to push the opponent below the kill threshold, then switch to Aqua Jet to clean. Damage done by Aqua Jet is only efficient when it closes a kill — it cannot justify itself on HP totals where a full-power attack would be worth more.
Named exception: Trick Room flips the script. Under Trick Room, speed is inverted — the slowest Pokémon acts first. This means Azumarill, already very slow, naturally acts first in Trick Room without needing priority. Here, Aqua Jet still fires in the +1 bracket before any priority-0 move, but since Azumarill was already first, the benefit is redundant — you'd be better off using Play Rough or Liquidation to leverage the turns. More importantly, Trick Room teams often run their own slow sweepers that expect to go first naturally; Aqua Jet doesn't stop that if the opponent is in the same priority tier as your move.
Water-immune abilities shut it off completely: Water Absorb (Vaporeon), Storm Drain (Gastrodon archetype), and Dry Skin (Toxicroak) all negate Aqua Jet — the move deals zero damage, and some of these abilities actively benefit (HP recovery, Special Attack boost from Storm Drain). Identify these before committing, especially in doubles where Gastrodon is a common pick specifically to wall Water spam.
Resistance check: Water is resisted by Water, Grass, and Dragon (×0.5). Grass cores like Ferrothorn and Rillaboom shrug off Aqua Jet without blinking — using it into these types is a hard misplay. Carry a coverage move for them, or route your cleaning through a different attacker.
Life Orb recoil adds up fast: If Basculegion runs Life Orb (×1.3 damage, −1/10 max HP per hit), every Aqua Jet fired takes a 10% HP bite. Three consecutive uses costs 30% HP from recoil alone — which can push Basculegion into OHKO range for priority moves it might otherwise survive. Choice Band avoids the recoil at the cost of move-locking. Know the math before you commit to a play pattern: if you're closing multiple targets with Aqua Jet in a row, the Life Orb tax is a real survival factor to track.