Please see link to Taiwan FCO Advisory - https://www.gov.uk/foreign-travel-advice/taiwan

• Foreign nationals are permitted to enter Taiwan provided they are not entering for study, tourism or to visit friends. You will need to apply for a visa before travelling.
• Foreign nationals entering Taiwan must provide a negative COVID-19 test report completed in the three working days prior to boarding their flight. Foreign residents of Taiwan are exempt from this requirement.
• On arrival in Taiwan you are legally required to self-isolate for 14 days if you have travelled from the UK.
• Travellers from destinations designated as low risk by local authorities may be eligible for a reduced self-isolation period.
• Limited transits are now permitted.

See Entry requirements for more information before you plan to travel. Also visit the Ministry of Foreign Affairs website for further updates  - https://www.mofa.gov.tw/en/theme.aspx?n=635352E3900FFF8E&s=8A33013523400F35&sms=BCDE19B435833080