She performed at Her Majesty's Theatre in London's West End; a role she held for fifteen months with critical acclaim.

[7] Cothi's soprano voice has made way to an array of opportunities for the singer, and has performed and travelled throughout the world in a variety of venues.

[9] Between 2005 and 2008, Cothi played the role of Davina Roberts, the conductor of "Côr Meibion Gwili" in Con Passionate, a Welsh language drama series on S4C.

In 2008, Cothi participated in the Faenol Festival, dueting with Sir Bryn Terfel and Michael Ball in front of 10,000 people.

The second series followed Y Goets Fawr (English: "The Stagecoach") which saw both presenters travel from Oswestry along the historic route from London to Holyhead, stopping for an evening of entertainment at five places along the way.

[17] In 2012, Cothi also presented Llais i Gymru, a Welsh–language singing competition with the aim of finding Welsh musical stars.

[23] On 5 June 2015, to mark BBC Music Day, Cothi set a new world record for the longest-distance duet ever made between two people.

[25] Between 23 and 25 October 2015, Cothi was one of twelve headline artists to perform at the Broadway to the Bay show in celebration of its 10th anniversary.

[27] In 2017, Cothi participated in Cyngerdd y 10 Difa, a Welsh-language singing entertainment show at Venue Cymru, Llandudno.

[30] On 30 March 2018, Cothi presented an hour long documentary on S4C looking at the work of the active charity Amser Justin Time.

The show also included the highlights of the 10th anniversary charity concert held in at Pontrhydfendigaid Pavilion in memory of her late husband.

[31] On 4 July 2019, Cothi hosted the annual Womenspire awards at St Fagans National Museum of History in Cardiff.

[32] On 8 June 2020, Cothi featured in an episode of Wonders of the Coast Path for ITV Cymru Wales, hosted by Sean Fletcher.

[34] In January 2021, Cothi participated in Canu gyda fy Arwr, a Welsh-language singing entertainment show on S4C.

[38] Following this, Cothi decided to raise awareness of pancreatic cancer by setting up a charity called Amser Justin Time, in memory of her late husband.

[43] In September 2013, Cothi, alongside 52 fundraisers successfully climbed Mount Kilimanjaro in support of Velindre Cancer Centre and her own charity, Amser Justin Time.