If you’re a US passport holder, you can currently travel New Zealand as a tourist for up to 90 days without a visa. However, if you're travelling after 1st October 2019, you'll need to apply for a ETA (Electronic Travel Authority). This ETA is basically a visa waiver, which costs between $9 and $12 NZDYour passport must not expire for at least 90 days beyond the date you depart from New Zealand.
New Zealand Working Holiday visa
Soak up the true culture of New Zealand by working there! Americans can apply for a Working Holiday Visa, which allows you stay for up to 12 months working and traveling around the country. You will usually get a response within a few days of applying asking for more information or letting you know the decision. Once approved, you have 12 months to arrive in New Zealand and can work for up to 12 months once you get there.
Visa and entry requirements are subject to change at any time. Please always check the current status with your applicable embassy prior to travel.