这个是美国先搞出来的,而且更贵。欧盟出于对等的方针才推出相似的要求。
ESTA applications may be made at any time, but travelers are encouraged to apply at least 72 hours prior to travel. ESTA has an application fee of $4, and if approved, an additional fee of $17 is charged, for a total of $21.[2] After approval, the authorization remains valid for two years,[a] or until the passport expires if earlier, for multiple trips during that period. Each person traveling under the VWP, regardless of age, needs a separate ESTA.[2]