I think the simplest answer is that no, you can't at least easily run another instance of Steam via the Flatpak. The two instances would need to hit separate configuration folders and so on. I think what might be possible is creating basically a full-system container with a separate /home and installing Steam there. You would then need to pass the X11/Wayland connection and other such stuff into that container so you can get graphics working. I think Distrobox might be able to do it, or you can do it the hard way directly with Podman/Docker or systemd-nspawn, LXC etc.

It would be a very roundabout way, but I guess technically you could run the native Steam client, and at the same time, run the Windows Steam client in Wine...

I think the easiest way to run two Steam instances, would be to have 1 Steam intalled via Flatpak, and 1 Steam installed as a system package. It seems like it should work.

As to how to do it purely with Flatpak, no idea - I just thought I'd share a few cents in case you found it helpful.

Last edited by DoctorJunglist on 4 Feb 2026 at 4:30 pm UTC

I experimented a little with the native (non-Flatpak) client and simply setting up another home dir and a pretend username is enough to launch a second client - at least as far as the login prompt, I don't have a second account to test further with.

$ HOME=/home/whizse/seconduser USER=seconduser steam 

Quoting: whizseI experimented a little with the native (non-Flatpak) client and simply setting up another home dir and a pretend username is enough to launch a second client - at least as far as the login prompt, I don't have a second account to test further with.

$ HOME=/home/whizse/seconduser USER=seconduser steam 

Wow that is way simpler than the abomination of a solution I came up with for streaming a game client and playing another locally simultaneously. I'm guessing you are on xorg because Wayland will not let you launch GUI apps if the user they are run with different from the user of the session, the workaround is the step 2 of the guide

https://old.reddit.com/r/linux_gaming/comments/xhgk6i/how_to_multiseat_gaming_w_streaming_1_instance/

Quoting: mr-victoryI'm guessing you are on xorg because Wayland will not let you launch GUI apps if the user they are run with different from the user of the session, the workaround is the step 2 of the guide

I'm on Wayland. But I didn't create a new user, just specified an alternate home dir and pretend username. I don't think USER is necessary but I didn't try without so left it in the example.

But I never tried further than the login prompt for the second client, so no idea if/how running a game works.

Quoting: whizseI'm on Wayland. But I didn't create a new user, just specified an alternate home dir and pretend username. I don't think USER is necessary but I didn't try without so left it in the example.

So you can launch another, isolated instance of Steam as if there are 2 users, without actually creating the 2nd user. That is even more cool.
I just tried your method. If I launch Steam with gamescope -e -- steam -gamepadui and stream a game, I get a black screen. I'm testing on an old macbook so there may be a hardware issue. Other than that It Just Works(TM). Your one liner has undone my 10+ step guide. Hats off.