Two new "cutting-edge" boats will "enhance" a police force's ability to keep people safe along the coastline, it has said.
The new Dorset Police vessels were funded by the Home Office, and have been described as a "significant upgrade" by the force.
Both of the new boats, a flybridge boat called Sentinel and a tactical rib called Invictus, have been purpose built for the force.
The flybridge vessel is the first of its kind for Dorset Police, and has a range of about 500 nautical miles, as well as a top speed of 48 knots.
Dorset Police Assistant Chief Constable Steve Lyne said the new additions would "allow us to better serve our communities and ensure we can put our specialist resources in the right places".
"It is only right that we have the capabilities to respond to an incident on the water in the same way that we would on land," he added,
The boats will be used by specially-trained marine officers to cover the Dorset coastline, including the 96 miles of the Jurassic Coast in the county.
They will be used for a variety of purposes, including water searches, identifying offences and anti-social behaviour at sea and on water, and officers and equipment to incidents.
Marine patrols along the coastline will also be carried out using the vessels, the force said.
Dorset Police and Crime Commissioner David Sidwick said: "Every year, thousands of people flock to Dorset to enjoy what our fantastic coastline has to offer, and these new cutting-edge vessels will not only enhance the Force's capability to enforce the law along our coastline but help keep people safe and deliver on our commitment to marine communities."