按官方说法(US CBP), B1/2中间去加拿大/墨西哥再回来不算重新入境。 https://help.cbp.gov/s/article/Article-751?language=en_US Traveling to other countries while in the United States on a B1 or B2 visa Visitor visas are nonimmigrant visas for persons who want to enter the United States temporarily for business (visa category B-1), for tourism (visa category B-2), or for a combination of both purposes (B-1/B-2). During your visit to the United States, you may visit Canada or Mexico for up to 30 days and re-enter the United State, if you re-enter within the timeframe indicated on the Form I-94 that you received when you first entered. For instance, if you arrived in the United States on July 10th with a B2 visitor visa, and on or after December 10th you decide you want to visit Canada or Mexico, you must keep in mind that the six-month period is up on January 10 and you will have to depart from the United States on that same day to avoid an "overstay" (unless you applied for an extension of stay). Note: The six-month period is computer-generated starting on the day you arrive in the United States. It is recommended that you do not wait until the last day of your six-month stay to make travel plans because unexpected emergencies may occur. If you visited other countries such as England or Costa Rica and then returned to the United States, your re-entry will be a new admission rather than a re-entry from a contiguous country during your initial visit, and the admission inspection may be more strenuous.
问题是怎么回来啊 入境美国不是要在境内待了几个月就要去境外待几个月的？
不是有B2签证嘛，只有没过期就直接回来啊
哦 我就听说 在境内呆了多久就要回国待过久不能马上再入境 想着出镜了是不是不能立刻入境
好像从美国去墨西哥再回来不算重新入境，I-94过期日期不变。
我爸妈19年去的Cancun之后就自动又给6个月了
从美国去墨西哥不用签证，呆30天内回美国没问题，但得在I94 valid period内
那你要小心，有的边境小哥不懂规则，可能错误的给了新的i94, 可能没人管，但细查起来可能这种延期不合法。
不要以为他们业务都熟练，我h1的时候没有有效签证去加拿大墨西哥都玩过，靠auto-reValidation回美国的时候就有边境officer不懂说我没有签证，我还得给他show文件说有这么个规定，他说哦这样🤔，于是放我进来。
是的。最好还是按照之前的期限离境，否则以后再入境大概率会有麻烦
I94过期日期在哪里能查到啊？
我觉得这个是case by case的，完全看入境官员的个人意愿。 我周围不少人（包括我自己），冬天的时候带父母去墨西哥度假，顺便看看能不能自动延长在美逗留期限 。我有限的10几个样本来看，大部分入境官员都会把这次入境看成重新入境给了6个月的逗留期限，但是也有三四个样本依然维持之前的I94的逗留期限。 忠告：从墨西哥入境时，避开亚裔模样的边境官员。
因为原则上b2每年在美国呆的时间不能超过离开美国的时间，除非你正式申请了延期。短期出境邻国又重新入境不算申请了延期。
按官方说法(US CBP), B1/2中间去加拿大/墨西哥再回来不算重新入境。
https://help.cbp.gov/s/article/Article-751?language=en_US
Traveling to other countries while in the United States on a B1 or B2 visa
Visitor visas are nonimmigrant visas for persons who want to enter the United States temporarily for business (visa category B-1), for tourism (visa category B-2), or for a combination of both purposes (B-1/B-2). During your visit to the United States, you may visit Canada or Mexico for up to 30 days and re-enter the United State, if you re-enter within the timeframe indicated on the Form I-94 that you received when you first entered.
For instance, if you arrived in the United States on July 10th with a B2 visitor visa, and on or after December 10th you decide you want to visit Canada or Mexico, you must keep in mind that the six-month period is up on January 10 and you will have to depart from the United States on that same day to avoid an "overstay" (unless you applied for an extension of stay).
Note: The six-month period is computer-generated starting on the day you arrive in the United States. It is recommended that you do not wait until the last day of your six-month stay to make travel plans because unexpected emergencies may occur.
If you visited other countries such as England or Costa Rica and then returned to the United States, your re-entry will be a new admission rather than a re-entry from a contiguous country during your initial visit, and the admission inspection may be more strenuous.