The UEFA Europa League champion had signed
All three will head overseas with Mourinho and their new team-mates on Thursday as the Portuguese prepares to start his second stint in charge of the club, and the 50-year-old is happy with the business he has done.
"Andre Schurrle is still so young but he already has great history because he plays in his national team, he has played Champions League and he played three complete seasons for Leverkusen," he told Chelsea's official website.
"So he is a player who is absolutely ready and he gives us more than one position in attack and adds quality. He will be important for us.
"Of course he needs to play and he will, because he is a player with great potential and physically he is more than ready. He is a natural athlete. By the technical and the tactical point of view of course he is a kid, he has to learn, but I think he is very open-minded and we analysed him for quite a long time."
Schwarzer is at the other end of the age scale at 40 and has penned a one-year deal as he looks to remain in the frame ahead of next year's FIFA World Cup.
Mourinho does not see a way he can dislodge
"To compete with Petr and to give us in that position what we have in any other position where we have competition and options, giving protection to each other.
"With Mark we have a goalkeeper who has played an incredible number of matches in the last 10 years in the Premier League and he is more than ready for this."
Mourinho, back in
The trio have been out on loan at West Bromwich Albion, Werder Bremen and Vitesse, but are now considered ready for action.
"They are good players with a very good value in the market and we have these players this season for free, after an investment that the club did before," Mourinho added.