By 2028, Guernsey, Jersey and Alderney will be equipped with the new Shannon Class lifeboat.
The RNLI says the Shannon class all weather lifeboat is better suited to local conditions and the nature of rescues around the islands.
Its research shows the majority of incidents happen close to shore and the Shannon is propelled by water jets, which work well in deep or shallow water.
The inshore lifeboats at St Peter Port, St Helier and St Catherines will also be upgraded with an anti vibration system and improved communication and management systems.
Adrian Carey heads up the south west region of the RNLI and says the new Shannon lifeboats are a logical improvement:
"Having the same class of all-weather lifeboat across the three islands means there is a standardisation of technology and equipment, improving the resilience of the RNLI fleet.
"It means qualified technicians can respond and support between the islands, and store critical spares and parts, reducing the reliance on delivery from the UK.
"Our volunteer lifeboat crew can also travel between the islands to take advantage of training opportunities, which cuts down on the travel time and time away from their families and day jobs."
RNLI chief exec, Peter Sparkes, says the investment is part of a long term strategy:
"Clear evidence shows the nature of lifesaving is changing, at a time when demand for our vital service is increasing. We must respond to this.
"We have reviewed and adjusted our lifeboat fleet and the placement of our lifeboats to meet the changing needs of our volunteers, supporters and communities we serve."
It is planned to replace Alderney's lifeboat first, then Guernsey's towards the end of 2027 and Jersey's in 2028.
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