Do United Kingdom passport holders need a visa to visit GY?

No visa needed. British (UK ordinary) passport holders can enter Guyana visa-free for tourism and are normally granted a stay of up to 30 days at the port of entry, extendable in-country through Guyana's immigration service. UK ordinary passport holders do not need a visa to visit Guyana for tourism or short visits. Guyana grants visa-free entry to British citizens, and immigration officers normally stamp in visitors for up to 30 days at the port of entry (some sources cite the broader 90-day exemption tier; the stamp granted in practice is 30 days). Extensions of one month at a time can be requested from Guyana's immigration authorities inside the country. Travelers should arrive with a passport valid for at least six months, proof of onward or return travel, and details of accommodation; border officials may also ask for evidence of sufficient funds. Visa-free entry covers tourism and short visits only; paid work, volunteering, business activity, or study require the appropriate visa or permit. Overstaying carries serious penalties, including fines, possible imprisonment, and deportation at the traveler's own expense. There is no electronic travel authorization or pre-arrival application required for short tourist visits. Guyana is in South America and is not part of the Schengen area, so the Schengen 90/180 rule and ETIAS do not apply.