Dunedin leaders are preparing to visit two sister cities in Scotland and Japan as part of a mayoral delegation.

Mayor Dave Cull will lead the delegation, to Edinburgh and Otaru.

City councillors Neville Peat and Andrew Noone are also going.

They'll be joined by Dunedin City Council community advisor Cara Paterson.

This month marks the 40th anniversary of Dunedin's sister city relationship with Edinburgh.

And next year a delegation from Otaru will visit Dunedin to mark the 35th anniversary of that relationship.

The mayoral delegation leaves Dunedin on Tuesday.

Costs of the trip - expected to be about $18,000 - will be paid for through the council's civil budget.