Cheltenham-based firm Bretherton Price Elgoods has forged a link with Heta, one of Estonia's largest law firms.
The two firms have signed an association agreement which took effect at the start of the month.
A lawyer from Heta is expected to be sent to the UK firm on secondment in the next month.
John Beever, the driving force behind Bretherton Price's Estonian practice, said that he first met people from Heta in 1993.
"We slowly built up contacts and communications and finally determined over the last 12 months, not least because Estonia was making a major bid to become a member of the European Union, that there would be a lot more cross-border work and referrals," he said.
It made sense, said Beever, to establish a co-operation agreement.
Kaido Philakas, Heta's managing partner, added: "Sometimes we need help in the UK and it is better for the client if you can recommend good lawyers and vice-versa."
The move is the latest initiative by the nine-partner commercial firm to develop an Estonian practice. The firm first got involved with the country through the local Rotary Club in 1992.
This was followed up by visits to Tallin, Estonia's capital city and, over time, the firm developed a string of Estonian contacts, notably with the Estonian Embassy in London.
In February last year, the Estonian ambassador Raud Malk visited Gloucestershire in recognition of the firm's efforts in promoting trade between the UK and the Baltic states.
Bretherton Price is one of the few foreign firms to establish a foothold in Estonia. Cameron McKenna, which is associated to Baltic Commercial Law Office in Tallin, is the only other UK firm to have links with a local firm.