Portsmouth's main rivals are near neighbours Southampton.
Prior to the mid/late 1960s, rivalry between Portsmouth and Southampton was largely nonexistent, as a consequence of their disparity in league status.
This derby match has been sporadic.
Since 1977, the teams have only played league games against each other in three seasons (1987–88, 2003–04 and 2004–05).
Including Southern League games, there have been 68 games between the clubs.
Another rivalry over the years was with Plymouth Argyle.
This rivalry was known as the Dockyard Derby, Naval Derby or Battle of the Ports.
Since the departure of Harry Redknapp to Tottenham Hotspur there has been a rivalry building between the clubs.
This may only be due to the Redknapp and the players who departed from Portsmouth to Tottenham.
The best known chant sung by Portsmouth supporters is the Pompey Chimes ("Play up Pompey, Pompey play up", sung to the tune of the Westminster Chimes) which is sung around Fratton Park.
The origins of the 'Pompey Chimes' lies with the Royal Artillery, Portsmouth's most popular and successful football team for much of the 1890s, who played many of their home games at the United Services ground in Burnaby Road.
The nearby Guildhall clock would strike the quarter hours and the referees would use the clock to let them know when the match should finish at 4pm.
Just before 4pm the crowd would lilt in unison with the chimes of the hour to encourage the referee to blow the whistle signifying full time.
The original words to 'The Chimes', as printed in the 1900–01 Official Handbook of Portsmouth FC, were:
Play up Pompey,
Just one more goal!
Make tracks! What ho!
Hallo! Hallo!!
With the demise of Royal Artillery after their expulsion from the 1898–99 FA Amateur Cup for alleged professionalism, many of Royal Artillery's supporters transferred their allegiance to the newly formed Portsmouth F.C. and brought the Chimes chant with them.