The Government have issued guidance in relation to travel internationally, which is available here: https://www.gov.uk/guidance/travel-advice-novel-coronavirus

A list of countries which are currently exempt from the requirement to quarantine on your return is available here: https://www.gov.uk/guidance/coronavirus-covid-19-countries-and-territories-exempt-from-advice-against-all-but-essential-international-travel.  Please be aware that this list may change.

Where you are required to do so under Government guidance, you must adhere to any quarantine period on your return to the UK.  You will not be able to compete during this time.

There is further guidance from the Government in relation to elite sports people https://www.gov.uk/government/publications/coronavirus-covid-19-guidance-on-phased-return-of-sport-and-recreation/elite-sport-return-to-domestic-competition-guidance

If you intend to rely on this exemption you need to be certain that you fulfil the criteria to be deemed an ‘elite sportsperson’ and that you fulfil the other criteria necessary for the exemption to be applied. 

We suggest you do this prior to any travel.

In line with the BEF’s position, any exemption will only currently be given where an athlete has travelled to a country on the UK Government’s exempt list to compete which becomes non-exempt during the period of competition.