The Mortlock Shield Championship, known for commercial reasons as the Port Lincoln Bendigo Bank Mortlock Shield Championship and commonly known as just the Mortlock Shield is an annual Australian rules football competition based in Port Lincoln, South Australia. The competition tis held annually at Centenary Oval and it consists of a round robinlightning football tournament with representative teams of leagues from the Eyre Peninsula and beyond. It is an affiliated competition of the South Australian National Football League (SANFL). The current champions are Western Eyre who won the 2025 edition of the carnival.
The current format of the Mortlock Shield consists of a single round robin structure composed of 5 representative sides of football leagues from around the Eyre Peninsula. The carnival is held over two days on the Kings Birthday long weekend (Saturday and Monday). The games are played under lightning football conditions with two twenty minute halves. The team on top of the ladder after four games played is declared champion and awarded the perpetual Mortlock Shield to commemorate their win.
Until 2021 teams formally played two full games (one on Saturday and one on Monday) against two select opponents and the team who finished top of the ladder was declared champion