Get a Global Entry Card from US Department of Homeland Security. If you have a tight connection between flights, this can be a lifesaver. You may bypass the long immigration lines when you return to the U.S. The application fee is $100 and lasts for five years.
Have a good book to read. There may be flight delays.
Drink plenty of water. It's easy to become dehydrated when you change climates.
Bring some cash for emergencies.
Bring sunscreen.
Add an international plan to your cellphone to avoid roaming charges. Call your provider and add a (usually) temporary international plan.
Put your phone in airplane mode to use your hotel’s wifi without accumulating roaming charges. Check with your carrier to see if this will work within your plan.
Notify your debit and credit card companies and your bank that you’re leaving the country. This helps prevent fraud alerts.
Bring an alternative power source for your cellphone, such as mini solar panels or a hand crank charger, for emergencies.
