Do you have to pass through customs in an American airport when you leave the US? or only when you come back?

Some countries want you to pass through customs & immigration on the way out but the US isn't one of them. You only have to report to customs & immigration on the way INTO the States not out of. There are exceptions to this rule and they usually involve visas, other paperwork and non citizens.

if you're prepared to stay contained in the secured section, i.e. Departure the front room, waiting on your next flight then you shouldn't ought to sparkling customs and Immigration. although with a 13 hour layover it will be constructive to verify in case you may want to get some style of excursion or in basic terms take floor transportation to the down city section to take a go searching. thus you may want to wish to sparkling customs and also you would opt for to look into visa criteria, i'm no longer particular in case you may want to wish a visa. There are a lengthy record of international locations that do not require a visa listed on the connected internet website.

NOT, no Customs and/or Inmigraion for EXIT!

But, yes on your way back.

Remember to either bring nothing or put everything into the checked lugagge. AS you also go through security checks at Houston!

Only coming back...you pass through the other country's customs when you go (in their airport)

normally you should only pass through them when you leave. in my country however, you have to pass trough them on both occasions and wait on a long line each time....and they say we're in the EU

only comming back..thats why you do not need a passport to leave for alot of places like mexico and jamica......but you need one to get back in