If you’ve played Marathon for a while, you’ve likely run into a frustrating problem: your vault fills up fast. After surviving a tough run and extracting great loot, you’re forced to decide what to delete to make room for new items.
The game initially limits storage to encourage engagement with the faction progression system and the in-game economy. However, there’s a key way to expand your vault, and understanding how to do so makes it one of the most crucial upgrades.
In this guide, I’m going to show you exactly how to increase your vault space in Marathon, what upgrades you should prioritise first, and a few strategies to make sure you’re not constantly deleting valuable gear.
How the Vault Works in Marathon
Your vault is your permanent storage in Marathon. All the loot you extract—like weapons, crafting materials, medical supplies, and rare resources—ends up here. Your backpack controls what you carry during a run, but your vault decides how much you can keep between matches.
While the vault appears spacious early on, it quickly fills as you extract more kits and materials. Without good organisation, you’ll have to sell or dismantle items you might want later.
The solution is expanding your vault through the faction progression system.
The Key Upgrade: CyberAcme Vault Expansion
If you want more vault space in Marathon, the upgrade you’re looking for is called Vault Expansion, and it’s found in the CyberAcme faction upgrade tree.
To access it, open your main menu and navigate to the Factions tab. From there, select CyberAcme, which focuses heavily on utility upgrades and quality-of-life improvements. Once you’re inside the CyberAcme menu, go to the Upgrades section, where you’ll find a node called Vault Expansion.
Purchasing this upgrade increases the number of rows available in your vault, allowing you to store more gear between runs. The first upgrade is especially valuable because it dramatically increases your storage capacity, giving you breathing room to hold multiple loadouts and crafting materials simultaneously.
This makes it a must-have upgrade early in Marathon.
All Vault Expansion Levels and Costs
Currently, Marathon offers five levels of vault expansion, each adding more storage rows. Each level also costs more than the last.
Level 1
- +8 rows
- 2,500 Credits
- 12 Unstable Diodes
Expansion Level 2
- +8 rows
- 4,000 Credits
- 22 Unstable Diodes
- 12 Unstable Gunmetal
Expansion Level 3
- +6 rows
- 5,000 Credits
- 27 Unstable Diodes
- 15 Unstable Gunmetal
Expansion Level 4
- +4 rows
- 7,000 Credits
- 30 Unstable Diodes
- 18 Unstable Gunmetal
Expansion Level 5
- +4 rows
- 10,000 Credits
- 50 Unstable Diodes
- 30 Unstable Gunmetal
You’ll also need to raise your CyberAcme reputation to unlock some upgrades, so progressing through the faction is important for getting more storage.
The Most Important Vault Upgrade Strategy
Players quickly notice expansion upgrades offer diminishing returns.
The first two upgrades are particularly efficient. For a relatively low cost, you gain 16 new storage rows, significantly boosting your gear storage.
After that, upgrades require more credits and rarer materials but provide fewer extra rows.
That’s why many experienced players suggest getting Vault Expansion Levels 1 and 2 first. After that, focus on upgrades that help you survive or fight better before going for the higher vault tiers.
This approach gives you early vault space without using all your resources.
How to Farm the Materials for Vault Upgrades
To unlock vault expansions, you’ll need two key crafting materials: Unstable Diodes and Unstable Gunmetal.
You can find these materials during runs on the Tau Ceti IV maps, often in buildings, loot containers, and high-value spots. Since you need them for several CyberAcme upgrades, always pick them up when you find them.to track the expansion upgrade in the CyberAcme menu. When you track an upgrade, the game highlights the required materials while you’re exploring the map, making them easier to spot during a run.
This helps you focus your looting and makes it much faster to farm for vault upgrades.
Don’t Confuse Vault Space with Backpack Space
It’s important to understand that vault upgrades and backpack capacity are two completely different systems.
Your vault acts as permanent storage; expanding it increases how much gear you can keep between runs.
Your backpack, however, determines how many items you can carry during an actual raid. Larger backpacks can be purchased, found as loot, or taken from defeated runners.
To bring back more loot, upgrade both your backpack for missions and your vault for storage at base.
Learning to manage both systems is an important part of mastering Marathon’s economy.
One Important Warning: Seasonal Resets
Marathon uses a seasonal progression system, which means some upgrades, including vault expansions, may reset when a new season starts.
If a seasonal wipe happens, you may need to unlock vault expansions again through faction progression. Treat each season as a fresh start and secure storage upgrades early.
Planning ahead can save you a lot of frustration when the next season starts.
Why Vault Space Is One of the Best Early Upgrades
Storage space is as valuable as weapons and armour in Marathon. Extra vault space gives you more options for loadouts, rare gear, and materials.
If you keep running out of space, don’t just delete your loot. Instead, invest in the CyberAcme Vault Expansion upgrades as early as you can.
Unlock the first two tiers, build up a good stash of weapons and gear, and you’ll find Marathon is less about inventory management and more about surviving your next run.