The three new Liverpool signings were joined by Mario Balotelli in the first training session of pre-season.
Matip became Liverpool’s second signing under Jurgen Klopp when he agreed a pre-contract agreement back in February. However he has had to wait until the summer, when his deal with Schalke came to an end, to complete the move.
Karius joined him at the club earlier this month, before Mane completed a £34 million move from Southampton at the end of last month.
A more recognisable face at Melwood was Mario Balotelli, with the Italian returning to the club after failing to convince AC Milan to turn his loan spell into a permanent switch.
It now remains to be see what impact these news signings will have at the club next season.
Karius is expected to replace Simon Mignolet as number one goalkeeper, while Matip is likely to be a regular in the heart of the Liverpool defence.
Similarly Mane is likely to be one of the first names on the team sheet, especially given the price the Reds have paid for his services.
Balotelli is another matter entirely though, with it as yet unknown if he will feature under Klopp or be moved on from Anfield for good.
Liverpool's Mario Balotelli in action with Hull's Tom Huddlestone