Police say around 50 people will be taking part in a co-ordinated search for missing teenager Jordan Cobb this morning.
Staff from the coastguard, Devon & Cornwall Police and Ministry of Defence Police will be scouring both sides of the River Tamar and the dockyard.
They're asking people to stay away from the foreshore and not to go out in boats, as they say it's not safe and will hamper the investigation.
The Devon search will go as far as the citadel, with the MOD searching the dockyard. On the Cornish side it will go from Mt Edgecumbe to Millbrook, including the St John’s and HMS Raleigh areas.
More top news
McLaren have signed Bristol teenager Lando Norris to their young driver programme, with a view to developing him towards an F1 career.
Investigations are continuing into a fire at the Riverside Leisure Centre in Exeter - which was attended by more than 100 firefighters.
The Prime Minister is being urged to intervene in the case of a Devon man killed in unexplained circumstances in Ukraine.