Intellectual property specialist Forresters has agreed a 10-year lease on 4,250sq ft at Downing's Port of Liverpool building.
Fifteen staff have transferred from Forresters' former office in Wirral to the new base in Pier Head.
Founded in 1884, Forresters specialises in all areas of intellectual property, including patents, trade marks, designs and copyright, with offices in Birmingham, Liverpool, London and Munich.
Ross Walker, North West partner, said: "We pride ourselves on building strong, long-term relationships and meeting with clients on a regular basis. Moving to a vibrant city centre office will bring us closer to our clients and will optimise client relationships."
Forresters' Liverpool office will cover the whole of the North West as well as North Wales.
The relocation is part of a UK-wide expansion programme, with Forresters recently investing in new offices in Birmingham and appointing three new partners across the UK.