People's Republic of China eSIM

The journey times decide it. Beijing to Shanghai is about 1,100 to 1,300 kilometres and takes four and a half to five hours by high-speed train, the fastest runs near four hours and eighteen minutes, against two and a half hours in the air. Beijing to Xi'an is around 900 to 1,080 kilometres, four to six hours by train or two by plane. Guilin is the exception: nine to nine and a half hours by rail from Shanghai but under three by air, so that leg is usually flown.

Build it from the fixed pieces rather than a round number. The Great Wall at Badaling or Mutianyu is a full day out of Beijing, on top of the Forbidden City, the Temple of Heaven and the Summer Palace. The Terracotta Army sits about 40 kilometres east of Xi'an, so it costs travel time as well as visiting time, and the walled centre wants its own day. Two rail legs of four to six hours each sit between the three cities. Add those up and the total appears.

Those are the two sections normally used as a day trip out of Beijing, and either one is a whole day rather than an afternoon. The Wall lies beyond the suburbs, well outside the subway network that ties the Forbidden City, the Temple of Heaven and the Summer Palace together, and neither section is reached on the Airport Express. Transport is arranged in advance, so save the return timing and the pickup point before you leave the city: hill terrain interrupts a handset more than the flat centre does.

Late March to May and September to October are the mild, drier windows for Beijing and Shanghai. Summer, June to August, is hot and humid, frequently above 35 degrees, and carries the heaviest rain of the year with sudden storms. Winter is cold in Beijing, which can sit well below freezing, and cold and damp in Shanghai. Guilin and Yangshuo, subtropical and further south, stay milder, with a wet season roughly April to August and a drier, cooler September to November regarded as the best time on the Li River.

Distance decides it: the site sits about 40 kilometres east of Xi'an, at the mausoleum of Qin Shi Huang, so the road counts in both directions. Half a day is the sensible minimum, and the intact city wall circuit, the Muslim Quarter or the Big Wild Goose Pagoda fill the remainder without another long transfer. Save the return details on the phone before setting out, because the route east leaves the city's metro area behind.

It buys a different landscape and a different kind of day. The Li River cruise covers about 80 kilometres of karst peaks between Guilin and Yangshuo, several hours on the water, with rice terraces and countryside at the Yangshuo end and Reed Flute Cave back near Guilin. The cost is distance: 1,540 kilometres from Shanghai and 2,110 from Beijing, nine hours or more by train from either, so the leg is normally flown — under three hours from Shanghai. On a short trip, the three-city rail circuit stays tighter.

As an itinerary it combines well, and Hong Kong is often placed at one end of a mainland circuit. For data, treat the two as separate destinations: a plan for mainland China does not automatically cover Hong Kong, and a Hong Kong plan does not automatically cover the mainland, so check the destination list named on the offer itself. Plan each leg on its own terms, the way you would already be booking its flights or trains separately.