The dramatic discovery of 12 boys and their football coach who had gone missing inside a cave in Thailand has captivated the world. Attention has now turned to the crucial task facing the Thai navy and the teams of international rescuers: getting the group to safety.

There are essentially four options for trying to rescue the boys – all of which are fraught with danger. The first two involve waiting for a passage to emerge or be created, which would allow the group to leave without going underwater. They could stay in the cave until the water either subsides or is pumped out, or rescuers could try to drill a new passage through to their refuge.

The other options involve trying to get the group out through the flood waters, either by teaching them to dive so they can swim out themselves, or wrapping them up with a breathing apparatus so they can be passed out like “packages” along a human chain of rescuers.

Rescuers are currently weighing up the different risks, but whatever option they choose, experts in cave diving and rescue say it is likely to be several days at the very least before any of the group are back above ground.

Wait for water to go down

Waiting for water to recede is risky because Thailand is at the start of its monsoon season. Rescuers have pumped some water out of the cave systems, but more rains are expected soon, and it could be months before waters are back down near the levels they were at when the group went in. Thai navy Seals were reportedly taking in four months worth of food supplies for the boys.

Create a new passage

Drilling down to reach the group does not appear to be practical. Rescuers are probing near the caves for other possible entrances, but have not found any that lead near the group’s refuge. Even if they do get close, the British Cave Rescue Council said the boys are “located in a relatively small space and this would make any potential drilling attempt as a means of rescue very difficult”.

Teach the boys to dive so they can be guided out

This seems extremely unlikely as cave diving is difficult even for people with experience and reportedly none of the boys can swim, much less use diving equipment.

They would have to learn to both swim and dive metres underground, then navigate through a passage that has proved challenging even for their extremely experienced rescuers, through water often thick with silt with near-zero visibility, managing strong currents and passages not much wider than their bodies.

Pass the boys out via a human chain of rescuers

The only other option is to fit the boys with full face masks, providing them with breathing equipment and a thick wetsuit to prevent hypothermia, then effectively passing them out along a human chain of rescuers.

However this would also be complicated. Parts of the cave system are reportedly so narrow that Thai Seal teams and the volunteer rescue divers had to remove their own breathing apparatus to get through, so it is not clear how the soccer team would be handed through those sections.

It would also be extremely slow, with the group brought out one-by-one using a kind of relay system to minimise risks. If they left as a group, and one person got stuck in a difficult section, it could put others at risk, rescuers said.