"This acquisition will almost double EFTel's broadband customer base to around 40,000, growing the company to 140,000 active accounts overall," EFTel said this afternoon in a statement to the Australian Stock Exchange.
aaNet has been making noises in public about a sale since at least December, with the buyer until today unconfirmed.
In the statement, EFTel chief executive officer Simon Ehrenfeld said his company had been working closely with Telstra to make the sale possible.
The heavyweight provides wholesale services to aaNet.
"Until early this week it appeared there was no viable process, but last-minute negotiations proved fruitful," said Ehrenfeld.
"We now have a path forward for other large acquisitions in the broadband space."
In February EFTel said a partnership with Westpac had allowed it to pursue an acquisition strategy. At the time Westpac gave EFTel an AU$3 million pilot facility.
In the past 18 months EFTel has bought a number of smaller ISPs such as Victoria-based Global Solutions Network and MyAccess, and Western Australia-based VianetAIP group.
In December last year EFTel changed its name from Datafast Telecommunications. Datafast acquired EFTel in the latter days of 2002.
Ehrenfeld was not immediately available for comment on how much the deal was worth, but the statement said aaNet had an annual turnover approaching AU$10 million.