As he made his way home on Friday aboard a RAAF C17, Harris wrote that he wasn't sure why he had become "the face of this rescue" and he felt that his heavily-publicised role was no more or less important than hundreds of others.
"The part we played has been made out to be a lot more noble than it actually was, we just consider ourselves lucky to have had some skills that we could contribute to the wonderful outcome," he wrote.
Harris paid tribute to the dive experts who were first on the scene, like Belgian diver Ben Reymenants and the "awesome foursome from Britain" of John Volanthen, Rick Stanton, Jason Mallinson and Chris Jewell.
Stanton and Volanthen miraculously found the Wild Boars soccer team huddling on a small mound in the cave, nine days after they went missing.
By the time Harris arrived on the scene, those divers had "already been doing the most extraordinary dives through the cave and laying the very robust rope which made all subsequent dives to the soccer team not only possible, but safe," Harris wrote.
"The efforts and skill of these guys in blazing this trail cannot be underestimated. Following someone else’s line is very much easier than finding your own way."
The four British divers did further supply dives to the soccer players, the coach and the four Thai Navy SEALs who stayed with the boys the entire time, he wrote.
Meanwhile, he wrote, the Thai and international communities sent in thousands of people to cater, provide communications, fill the cave with tonnes of water pumping equipment, rig the dry cave section with rescue gear and scour the bush for other entrances to the cave.
"I have never seen anything like it with man battling to control the natural forces of the monsoon waters," he wrote. "And all this time 4 brave Navy Seals sat with the Wild Boars knowing they were in as much danger as the kids."
Harris and Challen supported the all-star team of divers as they brought the boys out. He said the pressure on those divers "was immense and they never dropped the ball for a second".
When the boys and their coach reached the third chamber of the cave, US para-rescue teams, Australian Federal Police divers and Thai Navy SEALs were among a large team that assessed the boys before whisking them out of the cave to a field hospital, then flying them to a major hospital in Chang Rai.
Harris and Challen visited the boys in hospital before heading home.
The pair's role in the complex rescue operation was praised by Volanthen, one of the British divers, who said the boys found Harris' "bouncy" Australian accent to be "relaxing and reassuring".
"Dr Harry, the Australian doctor, he's very good, he's got a very good bedside manner, he's got a very bouncy Australian accent, and they seemed to find that quite relaxing and reassuring," he told reporters when he landed at Heathrow airport.
Volanthen said that he was pleased and relieved when he found the boys alive.
"But I think at that point we realised the enormity of the situation and that's perhaps why it took a while to get them all out," he said, adding: "We are not heroes. What we do is very calculating, very calm. It's quite the opposite."
Both Volanthen and Harris paid tribute to Saman Gunan, 38, the former Thai Navy SEAL diver who suffocated while replenishing air tanks. Volanthen said it brought a "bittersweet" taste to an otherwise "excellent" operation.