I. 24-hour port transit visa-free
一、 24小时口岸过境免签
The 24-hour transit visa-free policy can be found in the national migration administration's “Interpretation of the 24-hour transit visa-free policy for foreigners”:
24小时过境免签的政策可以参看国家移民管理局《外国人24小时过境免签有关政策解读》：
A foreigner who transits from China on an international aircraft, ship or train with a combined passenger ticket for a third country or region and stays within China for not more than 24 hours and does not leave the port of entry may be exempted from obtaining a visa, however, a temporary entry permit must be applied to the exit and entry frontier inspection authorities.
外国人持联程客票搭乘国际航行的航空器、船舶、列车从中国过境前往第三国或者地区，在中国境内停留不超过24小时且不离开口岸，可免办签证,但须向出入境边防检查机关申请办理临时入境许可。
In other words, in almost all of China's international airports, foreigners are not restricted nationality, except for special circumstances cannot enter the country, as long as do not leave the airport, can enjoy 24-hour visa-free transfer. Non-availability of round-the-clock visa-free transfers in the following special circumstances:
也就是说，在中国几乎所有的国际机场，外国人不限制国籍，除了特殊情况不能入境的以外，只要不离开机场，都可以享受24小时免签转机。不能获得24小时免签转机特殊情况如下：
The entry and exit frontier inspection organs shall not issue temporary entry permits to foreigners who are: (1) those who are not allowed to enter the country under the provisions of laws and administrative regulations; (2) those whose passports or other international travel documents have been valid for less than three months, or have been stamped by the visa authorities with their signatures refused; (3) those with records of illegal entry, exit, illegal residence or illegal employment within five years; (4) any violation of the provisions of the registration of accommodation within 2 years and the circumstances are serious.
具有以下情形的外国人，出入境边防检查机关不予签发临时入境许可：（一）具有法律、行政法规规定不准入境情形的；（二）所持护照或者其他国际旅行证件有效期不足3个月的，或者有我签证机关拒签章戳记的；（三）5年内有非法出入境、非法居留、非法就业记录的；（四）2年内有违反住宿登记规定行为且情节严重的。
The airports not included in the following 72-hour and 144-hour lists, such as Urumqi Diwobao, Nanchang Jiangbei, Nanning Wuwei, Changchun Longjia, Fuzhou Changle and Shenzhen Bao'an, can only apply to 24-hour visa-free.
不在下面72小时和144小时名单内的机场，比如乌鲁木齐地窝堡、南昌江北、南宁吴圩、长春龙嘉、福州长乐、深圳宝安等机场，只能适用24小时免签。
II. 72-hour airport transit visa-free
二、72小时机场过境免签
The 72-hour transit visa-free policy can be found in the national migration administration's "Interpretation of the 72-hour transit visa-free policy for foreigners in selected countries":
72小时过境免签的政策可以参看国家移民管理局《部分国家外国人72小时过境免签有关政策解读》：
Unlike the 24-hour visa-free transit, the 72-hour visa-free transit limits airports and nationality, and only citizens of the following 53 countries are granted the 72-hour visa-free transit (currently suspended in Japan and South Korea, so only 51 countries):
和24小时过境免签不同，72小时过境免签限制了机场和国籍，只有以下53个国家的公民才可以获得72小时免签（目前日韩暂停，所以只有51个国家）：
European Schengen visa agreement countries (24): Austria, Belgium, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland;
欧洲申根签证协议国家（24个）：奥地利、比利时、捷克、丹麦、爱沙尼亚、芬兰、法国、德国、希腊、匈牙利、冰岛、意大利、拉脱维亚、立陶宛、卢森堡、马耳他、荷兰、波兰、葡萄牙、斯洛伐克、斯洛维尼亚、西班牙、瑞典、瑞士；
Other European countries (15): Russia, Britain, Ireland, Cyprus, Bulgaria, Romania, Ukraine, Serbia, Croatia, Bosnia and Herzegovina, Montenegro, Macedonia, Albania, Monaco, Belarus;
欧洲其他国家（15个）：俄罗斯、英国、爱尔兰、塞浦路斯、保加利亚、罗马尼亚、乌克兰、塞尔维亚、克罗地亚、波黑、黑山、马其顿、阿尔巴尼亚、摩纳哥、白俄罗斯；
Americas (6): United States, Canada, Brazil, Mexico, Argentina, Chile;
美洲国家（6个）：美国、加拿大、巴西、墨西哥、阿根廷、智利；
Oceania (2): Australia, New Zealand;
大洋洲国家（2个）：澳大利亚、纽西兰；
Asian countries (6 , 4) : South Korea, Japan, Singapore, Brunei, UAE, Qatar.
亚洲国家（6个 4个）：韩国、日本、新加坡、文莱、阿联酋、卡塔尔。
The 72-hour transit visa exemption also limits the airport. Only the following three airports can obtain the 72-hour visa exemption (11 airports at the beginning, and then 8 have obtained the 144-hour qualification). At the same time, passengers cannot leave the specified scope of activities in brackets:
72小时过境免签也限制了机场，只有以下3个机场可以获得72小时免签（一开始有11个机场，后来有8个获得了144小时资格），同时旅客不可以离开括号内的规定的活动范围：
Guilin Liangjiang (Guilin City)
桂林两江（桂林市）
Harbin Taiping (Harbin City)
哈尔滨太平（哈尔滨市）
Changsha Huanghua (Hunan Province)
长沙黄花（湖南省）
Note that the scope of activity here in Changsha for the province, and several other airport activities only in this city.
注意这里长沙的活动范围为全省，而其他几个机场活动范围只是本市。
At the same time, passengers need to hold a 72-hour confirmed date and seat to the third country (region) connecting tickets. The United States-Xiamen-Hong Kong region was eligible for 72-hour visa-free travel at that time, while the United States-Xiamen-united states was not eligible for 72-hour visa-free travel according to the DP of past passengers, but the United States-Xiamen-Seoul transit-the United States, is available 72-hour visa-free. This means that as long as A-Chinese mainland-B, A and B are not from the same country, you get a 72-hour visa-free pass.
同时，旅客需要持有72小时内已确定日期及座位的前往第三国（地区）联程机票。美国-厦门-香港地区，当时符合条件可以获得72小时免签，而根据过往旅客的DP，美国-厦门-美国，是不可以获得72小时免签的，但是美国-厦门-首尔转机-美国，是可以获得72小时免签的。也就是说只要A-中国大陆-B，A和B不是同一个国家（地区)，那么就能获得72小时免签。
Passengers who meet the 72-hour transit visa-free conditions shall apply to the relevant airlines, and the airlines or passengers shall declare to the border inspection authority in person. The border inspection authority shall allow them to enter the country temporarily if they meet the conditions for transit visa-free conditions after examination.
符合72小时过境免签的旅客，应当向相关航空公司提出，由航空公司或者旅客本人向边检机关申报，边检机关经审核符合过境免签条件的，允许其临时入境。
III. 144-hour transit visa-free
三、144小时过境免签
The 144-hour visa-free and 72-hour visa-free are much the same, except at different ports of entry. The 144 hours are still valid only for citizens of the 53 countries listed above. The 144-hour rule is exactly the same as the 72-hour rule, which requires passengers to travel from country A to the Chinese mainland and then to country B. The 144-hour visa-free period covers the following ports and areas of activities. Visitors are not allowed to leave the areas of activities in brackets:
144小时免签和72小时免签大同小异，只是入境口岸有所不同。144小时依然只对上文中的53个国家公民有效。144小时的规则和前面的72小时完全一样，旅客需要从A国家（地区）前往中国大陆，然后飞往B国家（地区）。144小时免签有如下口岸和活动范围，旅客不可以离开括号内的活动范围：
Shanghai Pudong, Shanghai Hongqiao, Shanghai railway station, Port of Shanghai International Passenger Transport Centre, Wusongkou International Cruise Port, Nanjing Lukou, Hangzhou Xiaoshan, Ningbo Lishe (later joined) (Shanghai City, Jiangsu Province, Zhejiang province)
上海浦东、上海虹桥、上海火车站、上海港国际客运中心、吴淞口国际邮轮港、南京禄口、杭州萧山、宁波栎社（后加入）（上海市、江苏省、浙江省）
Beijing capital, Beijing West railway station, Tianjin Binhai, Tianjin cruise home port, Shijiazhuang Zhengding, Qinhuangdao Seaports (Beijing City, Tianjin City, Hebei province)
北京首都、北京铁路西站、天津滨海、天津邮轮母港、石家庄正定、秦皇岛海港（北京市、天津市、河北省）
Shenyang Taoxian, Dalian Zhoushuizi (Liaoning Province)
沈阳桃仙、大连周水子（辽宁省）
The 144-hour policy has been expanded twice, and the following ports have been added in the first expansion:
144小时后来范围扩增过了两次次，第一次扩增增加了如下口岸：
Xiamen Gaoqi, Xiamen Wutong Wharf (Xiamen City)
厦门高崎、厦门五通码头（厦门市）
Qingdao Jiaodong, Qingdao Wharf (Shandong Province)
青岛胶东、青岛码头（山东省）
Wuhan Tianhe (Wuhan City)
武汉天河（武汉市）
Chengdu Shuangliu (started as Chengdu City and expanded to 111 cities including Chengdu, Leshan, Deyang, Suining, Meishan, Ya'an, Ziyang, Neijiang, Zigong, Luzhou and Yibin)
成都双流（开始为成都市，后范围扩增到成都、乐山、德阳、遂宁、眉山、雅安、资阳、内江、自贡、泸州、宜宾111个城市）
Kunming Changshui (Kunming City)
昆明长水（昆明市）
The second expansion began on December 1,2019, but the outbreak began shortly afterwards, so many people are not aware of the second expansion:
第二次扩增在2019年12月1号开始，可惜不久疫情就开始了，因此很多人并不了解第二次扩增：
Ningbo Lishe (incorporated into the scope of activities in Jiangsu, Zhejiang and Shanghai)
宁波栎社（并入江浙沪活动范围）
Guangzhou Baiyun, Shenzhen Baoan, Jieyang Chaoshan (Guangdong province)
广州白云、深圳宝安、揭阳潮汕（广东省）
Xi'an Xianyang (Xi'an, Xianyang)
西安咸阳（西安市、咸阳市）
Jiangbei, Chongqing
重庆江北（重庆市）
The government website concludes that 20 cities and 27 ports are eligible for the 144-hour transit visa waiver, while 3 ports in 3 cities are eligible for the 72-hour transit visa waiver:
政府官网总结了20个城市、27个口岸符合144小时过境免签，3个城市3个口岸符合72小时过境免签：
After this expansion of the scope of application of the policy, a total of 18 provinces (autonomous regions, municipalities directly under the Central Government), 23 cities and 30 ports across the country have implemented a 144-hour and 72-hour visa-free transit policy for 53 national personnel. Among them, 27 ports in 20 cities, including Beijing, Tianjin, Shijiazhuang, Qinhuangdao, Shanghai, Hangzhou, Nanjing, Shenyang, Dalian, Qingdao, Chengdu, Xiamen, Kunming, Wuhan, Guangzhou, Shenzhen, Jieyang, Chongqing, Xi'an and Ningbo, have implemented a 144-hour visa-free policy for foreigners' transit, and have realized regional and port linkage in Beijing, Tianjin, Hebei and the Yangtze River Delta; Three ports in three cities, Changsha, Guilin and Harbin, have implemented the visa-free policy of 72-hour transit for foreigners.
这次扩大该政策适用范围后，全国共有18个省（自治区、直辖市）23个城市30个口岸对53个国家人员实施过境144小时、72小时免办签证政策。其中，北京、天津、石家庄、秦皇岛、上海、杭州、南京、沈阳、大连、青岛、成都、厦门、昆明、武汉、广州、深圳、揭阳、重庆、西安、宁波20个城市27个口岸实施外国人过境144小时免办签证政策，并在京津冀、长三角等地区实现区域、口岸联动；长沙、桂林、哈尔滨3个城市3个口岸实施外国人过境72小时免办签证政策。
Among them, the 144-hour visa-free access in the Yangtze River Delta, Beijing-Tianjin-Hebei and Pearl River delta is still very good. After visitors enter from Shanghai, you can spend six days to visit the scenic spots in Shanghai, Hangzhou and Suzhou and then leave the country.
其中长三角、京津冀和珠三角的144小时免签还是非常不错的，旅客从上海入境以后，可以花六天时间转一圈上海、杭州、苏州等包邮区名胜然后离境。
IV. Summary
四、总结
Although ordinary Chinese tourist visas are still not valid, foreigners from 53 developed countries who do not want or cannot apply for a three-month single Chinese visa, consider using a 72-hour or 144-hour visa-free curve to Chinese mainland a 72-hour (3-day) or 144-hour (6-day) stay. Here's a quick summary:
虽然现在普通的中国旅游签证依然没有恢复效力，但是53个发达国家的外籍旅客如果不想办或者不能办3个月单次的中国签证，可以考虑使用72小时或者144小时免签曲线救国前往中国大陆停留72（3天）或者144小时（6天）。下面是个小总结：
24-hour visa-free for citizens of all countries, applicable to all international airports in China.
24小时免签针对所有国家公民，适用中国所有的国际机场。
72-hour visa-free for citizens of 51 countries, applicable to Changsha, Guilin, Harbin, each airport has a designated area of activity
72小时免签针对53个51个国家公民，适用长沙、桂林、哈尔滨，每个机场有指定活动范围
144-hour visa-free for citizens of 51 countries, Beijing-Tianjin-Hebei, the Yangtze River Delta and the Pearl River Delta, a total of 20 cities, 27 ports
144小时免签针对53个 51个国家公民，适用京津冀、长三角和珠三角等总共20个城市27个口岸来自：求助得到的回答
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