The pair, who were tracked down thanks to tips from the public, told investigators they built the tunnel for "personal reasons" and their explanation has been verified, Const. Victor Kwong said.
Kwong said police have determined there was never any criminal intent or danger to public safety, and no charges will be laid.
"It literally was these two guys who had an idea to create a place to themselves to hang out in," he said.
"You think about a kid making a fort, digging a hole — add 15 years to that," he said.
Kwong said the men are not believed to be survivalists, adding they just "wanted to dig a tunnel."
The men had "no idea" they weren't allowed to dig in a public park and were apologetic during their interview with police, he said.
Toronto bylaw enforcement said digging on city land would be considered trespassing, which is enforced by police.
Police are not releasing the men's names, or any further details since the case is not a criminal investigation, but Kwong said there is no connection to York University, which is near the site where the tunnel was found, or the Pan Am Games.
Toronto police announced the discovery of the tunnel on Feb. 24 and released photos of the site, prompting media coverage across Canada and abroad.
The bunker, discovered in January by a conservation officer in a densely wooded area, is located 25 metres from the fence of the Rexall Centre, which is to host tennis events for the summer's Pan Am Games.
Inside, police say they found plywood wall supports, a generator and a sump pump, as well as a rosary with a Remembrance Day poppy nailed to a wall.
Police said the chamber was almost two metres high, 86 centimetres wide and 10 metres long.
Even though the bunker "looked impressive," the men have no formal training in construction, Kwong said.
Deputy police Chief Mark Saunders had said there was no evidence to suggest any criminal intent in the tunnel's construction, adding "there's no criminal offence for digging a hole."
But he asked for the public's help in solving the mystery and said police would continue to investigate until they discovered who built it, and that other authorities — including national and international security agencies — were notified.
The discovery of what has become known as the "mystery tunnel" made international headlines, while social media bubbled with theories that ranged from zombie hideouts to affordable housing.