It will provide a supportive out-of-hours service specifically aimed at people who are struggling to cope when other mental health services are not available.
Coastal West Sussex Mind (CWSx Mind) will be running this service as a member of Pathfinder West Sussex.
CWSx Mind deputy chief executive Kerrin Page said: “We are pleased to be able to offer people this important support right in the town centre.
“The aim is to prevent people going into mental health crisis, by having support when they need it.
“Having a safe haven, which they can attend when they need to, will help prevent the need for them to access urgent NHS care.”
The new service, funded by Coastal West Sussex Clinical Commissioning Group, will be based in the Frank Cave annexe at Guild Care’s Methold House, in North Street, Worthing.
It will operate for 46 hours per week from 6pm to 11pm on weekdays and midday to 11pm at weekends.
CWSx Mind already runs support sessions for people with mental health problems from Methold House for two full days each week.
Guild Care chief executive officer Suzanne Millard, said: “We are delighted to be working in partnership with Coastal West Sussex Mind.
“The Frank Cave annexe is a great new space that has been developed thanks to a grant from the National Lottery Big Lottery fund.”
CWSx Mind is now recruiting for staff and aims to open the safe haven in the new year.