How to cast farther

Quick answer

Strength pushes the cast further out, Weight pushes it deeper. Raise Strength first: distance reaches new waters, and new waters hold the better fish.

Strength is the stat that throws the rod further; Weight is the stat that sends it lower. Players mix them up constantly, and the fix is simple once you see what each one changes.

Strength versus Weight in one table

<div class="tbl-wrap"> <table> <thead><tr><th>Upgrade</th><th>What it changes</th><th>What you notice in-game</th><th>Priority</th></tr></thead> <tbody> <tr><td><strong>Strength</strong></td><td>How far out the cast travels</td><td>The landing point moves away from the shore; new water bands open up</td><td>First — it gates progression</td></tr> <tr><td><strong>Weight</strong></td><td>How deep the cast sinks</td><td>More fish per cast, and the roll table pulls from deeper species</td><td>Second — it multiplies an already-good cast</td></tr> </tbody> </table> </div>

The reason Strength comes first is not that it is stronger. It is that distance is what the map is built around: further water holds fish you cannot reach at the starting shore, and no amount of Weight lets you fish water your cast cannot land in.

Official Deep Fishing screenshot: the cross-section of water layers that a deeper cast unlocks

Reading the depth bar

The depth bar sits on the right of the screen and is the most useful HUD element in the game:

It fills as your cast travels down, so it tells you how deep this particular cast is going.
If you stop a cast early, the bar stops with it — which is exactly how the fast-cast key method works.
When your upgrades push the bar noticeably lower than it used to sit, that is your cue that a new species pool has opened.

The practical order of operations

Charge time first. A hold-and-release cast needs to travel; a half-charged cast wastes Strength you already paid for.
Buy Strength in bursts. Three or four Strength levels in a row beats one level of three different stats.
Add Weight once new fish show up. Weight only pays off when there is something better down there to catch.
Stop when the bar stops moving. Wall upgrades exist — once an upgrade no longer extends the cast, put the coins into the next stat instead.

Common myths, cleared up

"More Weight means bigger fish." Weight means deeper water and more fish per cast. Size comes from the pool that depth gives you, and from making the cast land further out in the first place.
"Bounce helps long casts." Players who have tested the four stats put Bounce last by a wide margin. It is a coin sink, not a range upgrade.
"Cap a cast to save time." Fast, shallow casts are only useful for key hunting, where the odds ignore your stats entirely. For money, let the bar run.

What to do right after

Once a full cast reaches the deepest water you can get to, your ceiling stops being range and starts being what you pull up: mutation multipliers on the fish themselves, and enchants on the rod to raise weight and luck.