Dunes wrecks may contain the databox for it (also the Stillsuit, I think). If you've already searched the Sparse Reef and Bulb Zone, go to the Dune wrecks. Suggest building a scanner room to ensure you find every possible databox.

You sure you've checked both Bulb Zone wrecks?

Edit: Do note that wrecks may include the SMALLER wrecks that don't get shown on most Subnautica maps online.

...What exactly are you looking for? The ingredients for it?

I want to say dunes wreck for the reinforced suit. Or possibly the mountains wreck. One of those I think is right. The other has the still suit blueprint. Not great locations for either of them, but one of those should be it. Unless you've already searched those wrecks.

You just have to find it. It's a data box, and if I remember right it has a chance to spawn 3 different large wrecks.

Here's some links:

Wiki for it

Interactive Map

Check the wiki for which ones, and use the interactive map to figure out how to get there. Good luck.

I generally find it on wreck in bulb zone adjacent to mashroom forest or wrecks near Lifepod 19.

One of the wreckage near the blood kelp zone? I completely forgot i just got it last week

Wrecks found in the outer ring biomes.

According to the Wiki, it spawns in a databox in the Bulb Zone Wreck, the Dunes Wreck, or the Sparse Reef Wreck.

To my understanding, databox locations get shuffled between their possible locations at the start of every game, but you should find it in at least one of these three locations in any game.

I go to keen 19 lifpod

There are 3 wrecks where you can find it. Have a look on the fandom wiki pages for details.

Have you tried going to life pod 19(2nd officer keen) location because there should be a wreck near there and it may contain it

You should perhaps consider that some of those areas has several wrecks and some of those wrecks has several data boxes, not just one. The boxes are not random, they always have the same blueprints in them so there are three blueprints that are still out there, you just haven't looked in the right spot.

I for the life of my cannot figure out what this ILS is… unless you mean ILZ? I wouldn’t be spending much time in the ILZ outside of my prawn suit anyways, so overall the reinforced dive suit seems kind of unnecessary.

i found it in dunes so i maybe you missed that?

Sparse reef wrecks! That’s the other place it can spawn. Make sure you check both (big and little, very close together).

Might sound like a dumb question but did you already find it?

I found a bunch of wrecks that had nothing in them. It wasn't until I looked them up that I realized that blueprints I already owned were supposed to be in them.

Meaning the game probably despawns things you already own to save memory.

make sure you’re going from the actual zero point and not your lifepod, other than that not sure what’s going wrong for you

Try the sparse reef wrecks. They're about a few hundred metres north of lifepod 19. Shouldn't be too hard to find during daytime.

It's about 300m deep in the bulb zone near the life pod next to the volcano

It is in the bulb zone, in a massive wreck surrounded by ampeels and some warpers so be careful. In my last playthrough i managed to find one in the wreck next to officer keen's lifepod. Its the smaller one, you need a laser cutter of course

Go to the eastern mushroom forest then into the bulb zone, there is a wreck which you’ll see which has it

I think they are in the bulb bush zone, but I could be mistaken.

Have a look here (spoilers warning maybe) https://subnautica.fandom.com/wiki/Reinforced_Dive_Suit?mobile-app=false

Nothing like the first time you roll up to an aggressive life form in a prawn. Not so awesome when it runs out of batteries deep in caves surrounded by said aggressive life forms.

What did you name it? My seamoth is OceanGate (probably too soon), and my prawn is TBD but I'm thinking Jerry P.

very cool but make sure to leave one arm normal so you are still able to pick up smaller items (like diamonds, lithium, etc.)

The name isn't written on the suit I don't think, but it'll show up as whatever you name it as a marker when you're far away.

Be careful, as it is common to assume that you have limitless power.