Internet Service Provider Plusnet is moving closer to Sheffield city centre from its headquarters in Tenter Street and operations in Victoria Quays.
The company is relocating to The Balance on Pinfold Street and taking 53,000 sq ft of space in the refurbished office block - the biggest office letting in the city for five years.
Chief executive Jamie Ford said: “This is an incredibly exciting time for our business and signals another milestone.
“With such rapid expansion over the last two years this move will enable all business operations including our customer services, to remain together under one roof.
“At the same time, the move gives us the space to necessitate further expansion as we continue to grow at pace and cements our commitment to Sheffield for the foreseeable future.”
The multiple award-winning broadband and home phone services supplier celebrates the 15th anniversary of its creation in Sheffield in February.
The company currently employs close to 700 staff, having brought its South African off-shore service teams back to the city in 2010 and lays claim to being one of the few ISPs to operate a UK based 24/7 customer service team.
Plusnet adviser, Knight Frank partner Tim Bottrill, said: “This is the biggest office let within Sheffield for the last five years.
“And it is something that we are proud of at our office in Sheffield.
“The Balance provides Plusnet with an excellent, new HQ facility in the heart of Sheffield. The building benefits from air-conditioned offices which include better meeting facilities; reception area; 24 hour security; landscaped recreational space; staff restaurant; cafe bar and parking.
“The building also provides excellent access to Sheffield’s extensive network of public transport trams and buses.”
Current occupants of The Balance building include HSBC and Hill Dickinson.
Plusnet has won six broadband industry awards this year and has been highly commended 13 times.
In September the company, which became part of BT five years ago, became officially Which? Recommended.
Jamie Ford added: “Our staff have worked incredibly hard to achieve this success and I am delighted that we are in a position to reward them with a state-of-the-art working environment.
“As we continue to grow, I hope the new building acts as another factor to attract local talent to our business.”