Vincent Clerc of the Copenhagen-based company's shipping unit said MSC Mediterranean Shipping Company SA and CMA CGM of France will form the P3 alliance with Maersk Line.
Clerc said that it will mean "even more efficient and competitive" operations.
The alliance will be an independently operated network with 255 vessels and is to start operations next year, depending on regulatory approvals. Maersk stressed the companies will continue to have fully independent sales, marketing and customer service functions.