They eventually found a dry landing spot, where they waited for nine days before being found by two British divers.
It would utilize parts used in the construction of the space firm's Falcon rockets, Musk says.
A team of engineers from Space-X and The Boring Company are on their way to Thailand. However, the inventor and entrepreneur has also floated some other ideas.
On Saturday, Musk tweeted that he was interested in designing "a tiny, kid-sized submarine" that would be "light enough to be carried by 2 divers, small enough to get through narrow gaps".
Jesse Lingard says Gareth Southgate has instigated a 'revolution' as England manager
Lingard stressed that Colombia would be unsafe opponents as England look to reach a first quarterfinal since 2006. Especially when balls are just dropping in for you and things are going for you.
Musk wrote to the user that while he suspects that the Thai government "has this under control", he would be "happy to help if there is a way to do so".
Musk said based on "feedback from Thailand", the engineers chose to build a "tiny, kid-size submarine" using a large silver tube meant to be affixed to a SpaceX Falcon 9 rocket.
In a statement to BBC, a spokesperson for The Boring Company said the company will offer more details once it works out with the Thai government what would be most helpful. "There are probably many complexities that are hard to appreciate without being there in person", said Musk in his tweet, necessitating the trip.
The next problem is time, where due to it being monsoon season in Thailand where it rains nearly everyday, the water levels in the cave are rising which means that it is a race against time to try and extract the boys and their coach ASAP.
A Thai Navy SEAL helping with the rescue operation died on Friday, underlining the dangers of navigating the flooded cave system even for those with experience.
Eight boys and the coach remain trapped, and experts are hoping to free the rest of the boys today.