The Saints enjoyed a strong return to the top-flight last season, securing a 14th-place finish despite a late run of poor form which saw them go their final six games without a win.
Pochettino has bolstered his ranks with the signings of Dejan Lovren from Lyon and Victor Wanyama from Celtic, and Fonte says they are joining a strong dressing room.
"The spirit in this team is fantastic. I've never been in a group as good as this one, and it's wonderful to be a part of this team," he told Southampton's official website.
"Everyone who comes in gets welcomed by the other lads, and I think they feel at home straight away because everyone in the dressing room is a good person and a good professional above all.
"We always find things to entertain ourselves, so it's been fun. We're here to do a job and push this club forward as a group."