How to upgrade inventory space in Borderlands 3

Learn everything you need to know to purchase SDUs and upgrade your inventory space in Borderlands 3.


With over a billion different guns to find and make use of you’re going to need a heck of a lot more inventory space to hold them all. Starting out, players in Borderlands 3 can only hold up to 15 different items in their backpack. That’s not going to cut it for very long. In this guide, we’ll show you where to purchase SDUs, which will allow you to increase your inventory space in Borderlands 3.

It should go without saying, but there are some mild spoilers ahead, so if you don’t want early-game events spoiled, make sure to check back after your first few hours.

How to upgrade inventory space in Borderlands 3

If you’re looking for a quick way to upgrade your inventory space in Borderlands 3, then we’re sorry to say that you’re going to have to wait a little bit. In fact, before you can purchase any kind of SDUs you’re going to need to make it off Pandora using the Sanctuary spaceship that Ellie has built for the Crimson Raiders.

Borderlands 3 - SDU case
The SDU case has a ton of great upgrades you can purchase.

Sanctuary is how you’ll get around the galaxy in Borderlands 3 and its also the main hub for a lot of the shops and little shindigs (like the beloved Moxxi’s) that you can visit during your time in the game. Once you make it to Sanctuary, head on down to Marcus’ Munitions. Marcus has set up shop on the ship and you can purchase a slew of items directly from him, including SDUs (or as he calls them “Super Duper Useful”).

There are quite a few types of SDUs available, but the ones that you’re looking for are the Backpack SDU. When purchased these SDUs will increase your backpack space by 3, giving you the ability to hold even more guns and items. Fantastic, right? Of course, if you can’t afford to upgrade your backpack just yet, then make sure you head over and pick up and lost loot you might have missed along the way, as you can sell it all to make even more of that sweet, sweet cash.

Borderlands 3 - backpack SDU
Purchase a backpack SDU to increase inventory space in Borderlands 3.

Now that you know how to upgrade your inventory space, head back over to our Borderlands 3 guide and walkthrough for even more help. We’ve got a ton of great articles to help you get started and stay on top of the food chain as you take on the Calypso twins and race to open every Vault.

Guides Editor

Joshua holds a Bachelor of Fine Arts in Creative Writing and has been exploring the world of video games for as long as he can remember. He enjoys everything from large-scale RPGs to small, bite-size indie gems and everything in between.

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