Arianne King

CEO and Solicitor Advocate

Arianne King CEO and Gaming Solicitor at Costigan King

Expertise

  • Gaming & Betting

  • Commercial Litigation

  • Corporate & Commercial

  • Construction & Energy

  • Fintech

  • Blockchain & Digital Assets

  • Dispute Resolution

Recognition

  • Ranked in Chambers & Partners for Gaming

  • Ranked in Legal 500 for Gaming & Betting

  • Ranked in Legal 500 for Commercial Litigation mid-market

  • Member of the IAGA (International Association of Gaming Advisors)

  • 'Most Influential Woman in Commercial Law 2019' in Acquisition International's Global Excellence Awards.

Arianne King is a Solicitor Advocate specialising in complex commercial matters across the UK and internationally. Ranked in Chambers & Partners for Gaming and in The Legal 500 for Gaming & Betting and Commercial Litigation (Mid-Market), she is described by Chambers as “a legal dynamo.”

She advises on high-value transactions and strategic regulatory matters, including debt and equity financing, restructuring, cross-border commercial agreements, intellectual property, acquisitions and regulatory compliance involving the FCA, DFSA, the Gambling Commission and the SEC. Her advice is recognised as “genuinely commercial and highly detailed, yet digestible,” combining technical precision with clear strategic direction.

Arianne is particularly known for her work in the gambling and online gaming sector. Legal 500 describes her as “unparalleled in her understanding of the betting and gaming world,” noting that she is “an immersed lawyer and participant in the sector who knows everyone and really fights for her clients.” She has extensive experience representing operators in investigations initiated by the Gambling Commission and advising on complex commercial transactions in online gaming.

In contentious matters, Arianne represents domestic and international clients in complex, high-value disputes across litigation, arbitration, adjudication and mediation. She is described as “a formidable solicitor who cares for her clients and is a constant source of support,” and is regularly instructed where financial and reputational stakes are significant.

Alongside her transactional and contentious practice, Arianne has developed a specialist focus on blockchain technology and digital assets. She advises on regulatory structuring, commercial strategy and dispute resolution in emerging technology sectors and is a recognised commentator on cryptocurrency, regulation and tax.

She was named “Most Influential Woman in Commercial Law – UK” in Acquisition International’s Global Excellence Awards.

Legal 500 notes that she “always puts the client first and goes above and beyond to make sure they understand the process,” and appreciate her “straight-talking approach” and the “excellent and thorough service” she provides.

Expertise

  • “Arianne King is a legal dynamo.”

    Chambers & Partners

  • “Arianne King gives everything a personal touch and I am very satisfied with the service I get from her.”

    Chambers & Partners

  • “Arianne always puts the client first and goes above and beyond to make sure the client understands the process. Her in-depth knowledge and vast experience in this sector and the law are invaluable.”

    Chambers & Partners

  • "Arianne has been our lawyer since the beginning and is excellent, I can't speak highly enough."

  • "Arianne provides an excellent and thorough service and we very much appreciate her straight-talking approach."

    Legal 500

  • "Arianne King always puts the client first and goes above and beyond to make sure they understand the process."

    Chambers 2024

  • "Arianne's in-depth knowledge and vast experience in this sector and the law are invaluable. Her advice is always genuinely commercial and highly detailed, yet digestible."

    Chambers & Partners

  • "Arianne is a formidable solicitor who cares for her clients and is a constant source of support."

    Legal500

  • "Arianne King of Costigan King is adept at assisting international clients with establishing new gaming businesses. She advises on a range of regulatory and compliance matters, in addition to providing expertise in connection with licensing and commercial mandates."

    Chambers & Partners 2025

  • "Arianne provides an excellent and thorough service and we very much appreciate her straight-talking approach."

    Legal500

  • “Arianne King leads the team and is a gambling specialist with extensive experience representing operators in investigations initiated by the Gambling Commission and advising on commercial transactions in online gaming.”

    Legal500

  • “Arianne King is unparalleled in her understanding of the betting and gaming world. She is an immersed lawyer and participant in the sector who knows everyone and really fights for her clients.”

    Legal500

  • "Arianne & her team handled the sale of our European marketing business to a large US firm. The sale, & subsequent 3-year earn-out, went smoothly thanks in large part to the excellent job they did in protecting our interests & diligently & efficiently handling all legal aspects of the transaction."

    Eleven Hundred Agency