Mobile carriers are in acquisition mode. German company Deutsche Telekom, which operates T-Mobile in the U.S., is making a bid to acquire super-regional carrier MetroPCS. Meanwhile, Sprint was also rumored to have plans to acquire MetroPCS, but had to hold off. We have also confirmation that Japan’s Softbank is planning to acquire Sprint Nextel.

Softbank has been eyeing the U.S. market for some time now, reports Reuters, and sources say the telecoms company is in talks with three banks in Japan to finance its acquisition bid. Sources close to the matter say Softbank plans to borrow 1.8 trillion yen (US$ 23 billion) in order to fund its acquisition.

Softbank may also look into acquiring other strategic assets in the U.S., including Clearwire. Such a move would help bolster Sprint Nextel’s network capacity, although analysts say Softbank might risk having too much debt exposure, given that Sprint has a net debt of US$ 15 billion, while Softank has a net debt of about US$ 10 billion, plus US$ 2 billion debt of smaller rival eAccess, which Softbank has recently agreed to acquire.

There are also reports that Softbank might likewise acquire MetroPCS in a two-step deal (first Sprint, then MetroPCS). At a combined 2 trillion yen (US$ 25.6 billion), this will be the biggest overseas acquisition by a Japanese company, and will also result in Softbank being one of the world’s major wireless carriers.

Will Softbank be the next big thing in the U.S. mobile telecommunications industry?