Members of the public are being told not to be alarmed if they see large numbers of firefighters on Scarborough's seafront tomorrow.
North Yorkshire Fire Service will be joined by other agencies, including the Maritime and Coastguard Agency, as they simulate a water rescue.
The exercise is designed to test the working arrangements between the various agencies involved.
It is due to begin at Marine Drive from 9am and last for around two hours.
Temporary station manager Stuart Hopkin said: "There will be a large number of emergency service vehicles on Marine Drive from 9am and we would ask people to take this into account if they are planning to travel anywhere, as there may be a need to shut parts of the road during some stages of the exercise.
"We will try to keep disruption to a minimum as far as possible."
The service regularly undertakes realistic training exercises like the one planned tomorrow.
They are designed to simulate operational incidents of varying complexity and make sure high standards in emergency response are maintained.
Mr Hopkin said: "Undertaking these kinds of training exercises helps us test the effectiveness of our response, and continually improve our service to the community."