Diu is an island separated from main land by a creek around. There are two bridges linking Diu with main land – one at Ghoghola to be approached from Una -Delvada side (12 km) and other from Una-Kodinar highway.
Diu (Div in Gujarati ) derived from ‘Dweep’ in Sanskrit was a flourishing port till the medieval period. Parsis when ousted from Persia in 696 A D took refuge first at this island before moving 20 years later to Sanjan in South Gujarat. Diu remained under the control of Rajput and then Mohmedan rulers of Gujarat till 1534 when Portuguese obtained permission from Bahadur Shah, Sultan of Gujarat to build a fort on the island and ultimately they occupied the territory. It was liberated on 19th December 1961.
Cavaleiro Lighthouse was built in 1897 at the centre of the Bastion of fort and a wick lamp was placed on it. The fort is under the control of Archaeological Department - their clearance is essential for visiting the Lighthouse.. Mr D. Alan Stevenson, the light house expert visited the island lights in February 1927 and found them to be of very low intensity.
A 4th order optic was introduced in 1937 which slightly improved the range of the light. In 1966 the tower was improved and a DA gas flashing light in 375 mm optical equipment of AGA make was installed. It was exhibited on 15th September 1966. The tower was declared unsafe in 1994. As such a trestle tower was erected nearby on which the same equipment but with halogen lamp and electronic flasher (JLWL) operating on solar energy, was placed and put into operation on 31st March 1994.In 1999 a new tower was constructed and the equipment with was shifted on to this tower. The new lighthouse was inaugurated by the Union Home minister Mr Lal Krishna Advani on 30th December 1999.