Thanks to the magic of PC Cross-Play powered by SHiFT, you'll be able to join forces with other PC players regardless of whether they purchased the game on Steam or the Epic Games Store
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Borderlands 3 supports PC Cross-Play between Steam and the Epic Games Store with the power of SHiFT Matchmaking. When launching Borderlands 3 for the first time on Steam, and on Epic after installing a new patch, you'll be greeted by a "PC Cross-Play" screen and the option to enable or disable this feature.
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Your save data can be transferred between the Steam and Epic PC platforms, but you will have to move your save files manually. By doing so, you run the risk of potentially losing your save files, so we strongly recommend that you make a backup copy of your save
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When Borderlands 3 is first released on Steam, you will only be able to send in-game mail to other PC players who own Borderlands 3 on the same storefront as you. We plan to patch in support for in-game mail being sent between the Steam and Epic platforms in the near future.
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If you're transferring an existing Epic Save file to your Steam account, be aware that you will not immediately receive Steam Achievements you may have already earned with that save file. Certain Steam Achievements may still be earned on that character based on completing the requisite criteria again, but at this time, we can't guarantee that Steam will register these Achievements consistently.