Hot answers tagged cancun
The second itinerary, the shorter by distance, appears to be the only correct one. Rome2Rio apparently has a little bug, confusing Santa Elena, Mexico and Santa Elena, Guatemala, near Flores, as shown on the Linea Dora website. So only the second option is valid. Looking at the itinerary on a map, this option looks not only the shortest in distance but ...
The only ESTA I know of is a system to obtain authorization to travel to the United States of America. Your description of your itinerary doesn't mention traveling to the USA at all, so you do not need to apply for ESTA. If your flight involved a connection in the USA, then you would need to apply for ESTA. But since you say you are traveling "directly" ...
If by round trip you mean between airport and hotel in both directions then price seems very reasonable given MXN518.36 estimate at Numbeo. Hotel shuttle buses are generally reliable and cope well with luggage.
ESTA is a Unites States government requirement for foreign citizens. However, if you're not visiting the USA, you have no need to get it. So as long as your flight from Amsterdam to Cancun (or any others) don't transit, land or layover in any US airport, you do NOT need to get this, no matter what your citizenship.
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