With Borderlands 3 being all about collecting the best loot, you’re going to be picking up a lot of it. Whether that’s in the numerous treasure chests that you’ll find or enemies that you kill, you never know when you’re going to need some inventory space to store a shiny new gun, shield, or grenade.
The good news is that you can increase your inventory size to make space for new items. The bad news is, you can’t do it right away. This guide will explain where you need to go to increase the default inventory size of 15 items and expand to something bigger.
You’ll need to have made it to Sanctuary. This is part of the main story and takes place after just a few of the main story quests where the Crimson Raiders head to Promethea. In this mission you will speak with Marcus who has a variety of upgrades that you can make to weapons, abilities, and storage capacity.
Increase Inventory Size by Purchasing Backpack Upgrade
Marcus has his own area on the ship called Marcus Munitions. The vendor is located at the green $ on the map. You’ll know you’ve reached the right spot when you see his sign and the two vending machines in front of his shop. Directly in front of Marcus are a bunch of Storage Deck Upgrades that can be purchased, each one has a different icon on it. The one you’re looking for is the Backpack if you want to increase the amount of guns and loot you can carry.
The Backpack SDU can be purchased at Marcus Munitions on Sanctuary
This Backpack SDU will permanently increase the number of items that you can carry by 3 each time you upgrade it. However, each time you upgrade the Backpack SDU it will cost you more to do so. The backpack can be upgraded 8 times to increase your inventory size to the max-level.
The backpack is only the inventory that you have on you at any time. You can also upgrade your Bank to store weapons or items as well. The bank can also be upgraded at Marcus Munitions. The bank also has up to 8 upgrades which increase the size by 5 each time.
To make sure that you’ve always got space in your inventory, make sure to sell items that you don’t need, transfer items you want to save to the bank, and increase the size of your inventory on Sanctuary.