Perth’s first Costco to be based north of the river is a step closer with the proposed Alkimos store receiving the official green light from planning authorities. On Tuesday, the $80 million development proposal received unanimous support from the Metro Outer Development Assessment Panel. Camera Icon Concept images of the approved Costco warehouse in Alkimos. Credit: SuppliedCamera Icon The planned site of the Alkimos Costco. It entered the Australian market in 2009 and opened its first Perth warehouse at Perth Airport in 2020, followed by a second in Casuarina in 2022.