Christian Johnson Lueking, 36, of Raynes Park, London pleaded guilty to one offence of encouraging the showing of indecent images of children earlier in June.
He will be sentenced at Kingston Crown Court on August 18.
Colin Radcliffe, operations manager at the NCA’s child exploitation and online protection (CEOP) command, said: “Darren Williams drove children to activities where they would play sport and have fun together.
“As it’s clear that he believes children can be horrifically abused for his pleasure his arrest was a vital intervention.
“These men thought they’d found a corner of the internet where they could avoid the consequences of participating in abuse.
“They were wrong and others like them should know NCA officers have skills and tools that mean no one seeking to harm children is safe from the law.
“Protecting children is an integral part of the NCA’s mission and our officers are dedicated to ensuring people like these are brought to justice.”