International Commerce Secretary Liam Fox signed the take care of his South Korean counterpart Yoo Myung-hee in Seoul.
Chief investment officer at Kleinwort Hambros, Mouhammed Choukeir commented: "in so far as a (UK-S Korea) deal has been struck that's a landmark moment".
It would duvet South Korean exports along with vehicles and auto parts.
Corporate Relations Director, Asia Pacific, Paul Kelleher of alcoholic beverages firm Diageo said he "warmly welcomes" the agreement, according to the communique, while Grant Hughes, the managing partner of law firm Clifford Chance, said: "We are pleased to hear the news of a trade deal which will allow for firms such as ours to maintain our local presence".
"This means that whatever happens with Brexit, there will be total continuity in trade between our two countries and the basis for an ambitious future free trade agreement when we leave the European Union", tweeted Fox.
Strikingly, the EU-Japan FTA, which entered force this February, is not included in the list. Some changes were made to the existing Korea-EU FTA in the latest bilateral agreement. South Korea exports largely vehicles and ships to Britain, while it imports crude oil and vehicles. The two countries now need to seek ratification from their respective parliaments before October 31.