I will be in London for most of just a single day plus one evening & overnight stay, and plan to find some fun things to do as a tourist. I also plan to buy some souvenirs, sample some food, and so on.

Can I rely on credit cards in most places, or do I need to get some currency? If so, is it better to exchange in advance before I arrive (in the USA), or can I wait until in the country? Where in the country can I find a more reasonable exchange rate—I suspect Heathrow might not be the best place to do that.

I will be in London for most of just a single day plus one evening & overnight stay, and plan to find some fun things to do as a tourist. I also plan to buy some souvenirs, sample some food, and so on.

Can I rely on credit cards in most places, or do I need to get some currency? If so, is it better to exchange in advance before I arrive (in the USA), or can I wait until in the country? Where in London can I find a more reasonable exchange rate? I suspect Heathrow airport might not be the best place to do that.

I am from the USA and will soon be passing through London twice on two different Sundays.

• One Sunday, arriving on a flight in Heathrow around 7am and leaving by train no later than 6 or 7pm. Or, could visit locations reachable by train between London and the coast to the south.

• Another Sunday, arriving on a flight in Heathrow around 3pm, staying overnight and departing on a flight in the morning. I could do something early but likely need to be to the airport by 7am (so, early breakfast)?

How can I use my relatively short time in London effectively to get some tourism done?

• What is worth doing for these short times?

• Will merchants accept credit cards everywhere, or is it better to get some hard currency? Is it best to get currency in advance, or wait until arrival, and if so, where can a decent exchange rate be had?

• I'll be on the southern coast for a week and will have evenings to myself, so anything that can be done there I can skip in London.

• Pubs, sports, the darker side of night life are not of interest.

• I enjoy food (keto, though), technology, curio shops, random famous touristy locations, comedy, magic, trance music, skilled street musicians (especially drummers or other kinds of rhythm). Museums, maybe (not art).

• Need to buy some souvenirs or gifts for friends & family.

• Could use advice on travel adapters or converters.

I will be in London for most of just a single day plus one evening & overnight stay, and plan to find some fun things to do as a tourist. I also plan to buy some souvenirs, sample some food, and so on.

Can I rely on credit cards in most places, or do I need to get some currency? If so, is it better to exchange in advance before I arrive (in the USA), or can I wait until in the country? Where in the country can I find a more reasonable exchange rate—I suspect Heathrow might not be the best place to do that.