Yes.

Hi @Karlehib.

Welcome to the Sonos community and thanks for reaching out. Allow me to help you out by sharing some guides.

Yes, you can add 2 Sonos Play 3 as surround sound to your Sonos Beam. This information is also discussed on surround sound guidelines and limitations and here is the guide on how to add your Sonos Play 3 as surrounds to your Sonos Home theater system.

I hope this helps answer your question.

Please let me know if you still have any other questions or concerns. Everybody is welcome here in the community.

Thanks,

Thanks for your reply, would it be best to position the play 3's either side of the beam or could I position them behind me 

Hi @Karlehib.

Thanks for the immediate response. I would recommend placing them in the rears as they would be generating surround audio. It would not be a good choice to put them in front as you might not get that surround audio feeling if your surround audio is in front and not placed at the back.

Please let us know if you still have any other questions or concerns. There everybody learns something from everyone. 

Thanks,