雖然可以免簽赴美的民眾很多但是留學生、赴美進行文化和學術交流的人士、赴美採訪的記者以及赴美就業的民眾，依然需要申請美簽。

While many people can travel to the United States under the Visa Waiver Program, students, cultural and academic exchange visitors, working reporters and those seeking employment in the United States will still need visas.

如果護照內仍有有效的B1/B2美簽在過期之前都可以用這個簽證赴美旅行美簽過期後您可以選擇利用免簽計畫赴美也可以選擇重新申請B1/B2簽證。換句話說，若是您擁有有效的B1/B2簽證就不需要到旅遊許可電子系統(ESTA)進行註冊以使用免簽待遇。

If you still have a valid B1/B2 visa in your passport, you are welcome to travel on that visa until it expires. When it expires, you may choose to travel on the Visa Waiver Program or renew your B1/B2 visa. You are not required to sign up for the Electronic System for Travel Authorization (ESTA) and use the Visa Waiver Program if you have a valid B1/B2 visa. 

資料來源: 美國在台協會

簽證申請Q&A請參考http://www.ait.org.tw/zh/vwp.html