Chelsea have already recruited Andre Schurrle, Marco van Ginkel and Mark Schwarzer this summer.
Mourinho has stated that the only other player the club are interested in signing is Manchester United's unsettled striker Wayne Rooney.
And with no players expected to leave Stamford Bridge, the Blues boss feels he now has time to fully prepare his squad for the new season, which starts on 17 August.
"The sooner you have the players, the better," said Mourinho. "You know the squad you have, you know what you have to work with, you have time for that.
"Many clubs are waiting to the last moment to make their decisions. The problem is that those decisions affect not just one or two clubs, but a lot of them.
"The one who sells has to go and buy, then they have to buy to replace, so no club is safe.
"Until the last minute somebody can go there and steal a player. I don't mean steal a player, but steal the balance that a manager has when he's working with a team.
"In that aspect, we are lucky because we don't have players to sell, so none of my players is leaving under any circumstances.
"That's good for me, but many teams will be until the last moment under pressure, without knowing how the squad is going to be."
Mourinho has also laughed off suggestions that he is playing mind games with Manchester United counterpart David Moyes.
The Portuguese recently praised Moyes, who left Everton during the off-season to succeed Sir Alex Ferguson at Old Trafford.
When it was put to Mourinho on his arrival in Jakarta, where Chelsea play an All-Star XI on Thursday, that his compliments towards Moyes were a calculated act, the Blues manager replied: "If to say that my colleague in Man United is a great coach, he deserves success, he deserves time to work, he didn't win trophies at Everton because it's difficult to win trophies there... If to speak good about him is to play mind games, what do you say if I speak bad about him?
"The best thing is not to speak, and if I don't speak nobody says nothing."