Tethering is sharing the mobile data from one device, usually your phone, with another device that has no connection of its own. Your phone gets online through its eSIM, and a laptop, tablet, or second phone borrows that connection to reach the internet. It is the practical way to get a work laptop online in a hotel room, a cafe, or an airport lounge without hunting for public wifi.
There are three ways to do it, and the labels describe the cable or radio in between. USB tethering runs a cable from phone to laptop: it is the fastest and steadiest option and it charges the phone at the same time, so it suits long working sessions. Bluetooth tethering is wireless and very light on battery, but slow, best kept for email and messaging rather than video. A wifi personal hotspot turns the phone into a small wireless access point that several devices can join at once.
That last option overlaps with what people call a mobile hotspot. The difference is mostly framing: tethering is the general act of sharing one phone’s data, while a mobile hotspot specifically means the wifi-broadcast method, whether it comes from your phone or a dedicated pocket router. On a trip, tethering off your travel eSIM in a dual SIM phone keeps every device you carry online through a single prepaid plan. Just watch your allowance, since laptops burn through data far faster than phones. For more on staying productive abroad, see our eSIM guide for business travellers.