The companies announced on Monday Optus would buy 100 per cent of Seven's Vividwireless, and acquire the operating business, customer base, spectrum licence and 4G network.
Baker & McKenzie has acted for Optus on the deal, led by partner James Halliday and Rodney Stone. Through the purchase, Optus will gain access to up to 98MHz of spectrum in the 2.3GHz band.
Clayton Utz acted for Seven.
"This deal contained several unique elements, and will allow Optus to continue to deploy its cutting edge 4G technology," Baker's Halliday said.
Seven Group chief executive Peter Gammell said Vividwireless would be better able to deploy its 4G wireless broadband services under Optus than might otherwise be the case.
In addition to some other conditions, the sale remains subject to Australian Competition and Consumer Commission as well as Foreign Investment Review Board approval.