Staff will take visitors around the 19-acre site on top of Portsdown Hill, telling stories from its 150 years of history.
The Victorian fort was built in the 1860s as part of a ring of fortifications to protect the naval city of Portsmouth against a potential invasion by the French, which never materialised.
Although never used for its original purpose the Fort played a significant role in both World Wars; as barracks for troops waiting to be deployed to the front line in the First, and as an anti-aircraft ammunition supply depot during the Second.
Today Fort Nelson is a national museum, housing the country’s collection of arms and artillery, run by the Royal Armouries – general admission is free.
The new tours will run on Wednesdays during September at 11am, 1pm and 2:30pm. The tours can be pre-booked in advance or on the door, if capacity allows. Tours cost £5 per person and are suitable for ages 12+.
Private group tours, for up to 20 people, can be arranged during term time by emailing fnenquiries@armouries.org.uk.
Elizabeth Puddick, Public Engagement Manager at Fort Nelson, said: “We are pleased to relaunch tours back at the fort as it is a wonderful way for visitors to get an in-depth history of this fantastic Victorian Fort.
“Fort Nelson is a living history lesson on the doorstep of Portsmouth so come and discover history on the hill this autumn.”
Fort Nelson is open Tuesday to Sunday 10am to 5pm during term time and daily in the school holidays.