You can arrive in the UK at any time up until the 'valid until' date, but remember that this is also the last day that you are permitted to stay in the UK.
People Also Ask
Can I still travel 2 weeks to my US visa expiration date? Yes, you can still travel up to two weeks before your US visa expiration date.
American Visa UK: What can you do? Because Americans are known as non-visa nationals in the UK, to answer the question do American citizens need a visa for UK? They don't. American citizens are able to visit for up to six months without a visa.