"When we received offers from Japan and South Korea, we accepted immediately, because we'll face China in our first match in the World Cup", Guimaraes told El Heraldo newspaper.
"It was also a good opportunity for my players to get to know the stadia and find out what they need to improve before the finals.
China are not only Costa Rica's first opponent but also one of the teams they need to beat to reach the second phase of the tournament.
Guimaraes also made it clear that the tour was "the last chance" for some players who were still struggling to convince him that they deserve a place in the squad.
He said that 70 per cent of the squad is already chosen and he is only waiting for injured players such as Paulo Wanchope, Jervis Drummond and Reynaldo Parks to recover.
The Nacion newspaper suggested on Monday that defender Mauricio Wright and forward Winston Parks did enough on tour to guarantee their places on the final squad list of 23.
Before losing to South Korea, Costa Rica drew 1-1 with Japan last Wednesday.