Pacific's IT operations manager Jason Sinclair said in a statement that his company was "beginning to outgrow our current Sydney environment".
Moving the equipment to Global Switch's facility at Ultimo would operationally "be extremely efficient for Pacific", he said.
The IT manager said customers would be disconnected for a short time during the six-month moving window, during which time both facilities would run simultaneously to provide redundancy.
"We'll work with every co-location customer so they're only disconnected for two hours," he said. "DSL customers will only be disconnected once for about five minutes."
Pacific also has data centres in Melbourne, Newcastle and Brisbane, plus "equipment in Perth and Adelaide", but a spokesperson for the company said there were no plans to move that hardware around.
The spokesperson declined to disclose how many co-location customers Pacific services through the datacentre, but did say the ISP has over 20,000 business customers in total, with around 12,000 of those also buying value-added services like co-location hosting or managed security.
News of Pacific's move comes as the nation's largest Web hosting company WebCentral was yesterday forced to tell customers it had temporarily shut down a Brisbane datacentre in case equipment overheated after the centre's water supply was cut off.
ZDNet Australia has since learned telco AAPT's datacentre in the same building was unaffected by the problem due to the fact it had its own dedicated water supply.