Solomon Islands police say they are still to recover the bulk of the money stolen from two Asian businessmen attacked on Sunday a week ago while travelling to Talagi from Guadalcanal.
The robbers had made off with about $US40,000 in cash.
The men were set upon when the skipper of the boat they were travelling in offered assistance to another vessel that had appeared to have broken down.
The police commissioner Mathew Varley said three men from Ngella have been charged with robbery.
Mr Varley said his staff are still trying to find most of this money.
"We have recovered a small amount of cash but our investigations are ongoing. We are also looking into the circumstances behind this robbery and whether or not there were more suspicious circumstances at play as to how this robbery took place."