Ozen is the lifeblood of every run in Tides of Tomorrow. From the moment you wash up after the deep ocean opening, the game makes one thing clear: plastemia is coming for you, and ozen is the only thing slowing it down. Running dry at the wrong moment does not just hurt your health bar, it can end your run entirely. Here is everything you need to know about finding ozen fast and spending it at exactly the right time.
Where Does Ozen Come From?
There are four main sources, and each one has a catch worth understanding before you commit to a strategy.
Shared chests
Every location past the prologue contains a yellow chest, but these are shared resources across all Tidewalkers. If the player you chose to follow already looted it, the chest is empty for you. Before you commit to following a specific Tidewalker, check the markers at the bottom of the screen during the selection phase. Those markers tell you whether the chest at the next location still has ozen waiting inside. Choosing your follow target based on this information is one of the fastest ways to guarantee ozen income without any risk.
Merchants
Merchants appear frequently throughout the story and occasionally during ocean events. They trade ozen for scrap, which makes scrap management directly tied to your health. The same shared-resource rule applies here: if the previous Tidewalker spent the merchant's stock, there is nothing left for you to buy. Prioritizing merchants early in a location, before another player can drain their inventory, is a habit worth building.
Check the Tidewalker selection markers before every new location. A chest icon with ozen shown means the previous player left stock behind. That single habit can save a run.
Hidden exploration spots
Certain story segments contain hidden locations with ozen boxes tucked away off the main path. These are the cleanest source in the game because they do not depend on what another player did before you. No shared pool, no depleted stock. Seeking these out during every run should be a default habit, not an afterthought.
Ocean events
Once you finish a story segment, ocean events become available and they are a strong ozen source. Treating ocean events as mandatory between story beats, rather than optional diversions, keeps your supply from falling dangerously low heading into the next island.
Story choices
Some narrative decisions directly affect your ozen count. Certain choices ask you to hand over ozen, and while some of those situations return it or turn out to be a bluff, others cost you permanently. Knowing that these moments exist means you should never enter a major story decision with a bare inventory.
How to use ozen without wasting it
Having ozen is only half the problem. Spending it at the wrong time is just as dangerous as not having enough.
Consuming ozen restores one bar
Do not top off your health bar just because you can. Each time you complete a story segment and leave an island, the game removes two HP bars. Arriving with a full bar means you burned ozen that immediately disappears.
The timing rule that saves the most resources is straightforward: enter each island with one HP bar, then consume two ozen just before you leave. That way you absorb the two-bar deduction without wasting anything on bars that were going to vanish anyway.
Keeping your HP between one and three bars at all times is the safest operating range. Going higher than that is almost always wasteful given how reliably the game strips health at story milestones.
What's the fastest way to build an ozen buffer?
Combining all four sources in the right order makes a big difference. At the start of each new area, check the Tidewalker selection screen for chest markers. Follow whoever left ozen behind. Hit the merchant before the story drains their stock. During exploration, take every side path that looks like it might hide an ozen box. Then run ocean events between story beats to top up.
That loop, repeated consistently, keeps you well above the danger zone without relying on lucky choices or favorable narrative outcomes.
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