# What Is an ISP (Internet Service Provider)?

> An ISP sells you a connection to the internet, home or mobile. What splits the two, and why only the mobile kind still works once you have left the house.

Phones and networks · Published 2023-06-05 · Updated 2026-09-01 · 5 min read

Page: https://esimradar.com/blog/internet-service-provider

![A home internet router standing on a shelf beside a television.](https://esimradar.com/blog-images/internet-service-provider/hero-18071864-1280.webp)

*This box is a fixed ISP’s whole product. It plugs into one address, and packing it in a suitcase would not change that.*

An ISP, or internet service provider, is a company that sells you a connection to the internet. The term covers two different products rather than one: a fixed ISP wires a connection into a building, and a mobile ISP sells the same access over a cellular network to a device that moves. Your home broadband is the first kind. Your phone’s data plan, and any eSIM you buy for a trip, are the second.

The two are not interchangeable, which is the entire reason to know the difference. A cable modem wired into a wall in Chicago does nothing for you in Cairo. The kind that will is the mobile kind, sold by a carrier at home or, for a trip, by a travel eSIM provider using someone else’s towers.

> **Note:** Turning Wi-Fi on when you land does not connect you to anything by itself. A Wi-Fi radio only joins a network it already has credentials for, and a hotel’s or an airport’s network is not one you have used before. What actually gets a phone online away from a saved network is mobile data, on whichever network your carrier or eSIM has an agreement with in that country.

## The two kinds, defined by where they end

Most telecoms regulators draw the line at the same point the U.S. Federal Communications Commission does. Its own [broadband service definitions](https://docs.fcc.gov/public/attachments/DOC-402905A1.pdf) state that fixed broadband "refers to any type of broadband service that terminates at a specific end-user premises," while mobile broadband "refers to a service that allows end users to receive information from and/or send information to the Internet from a mobile device and using a mobile network." One product is nailed to an address. The other travels with the device that holds it.

The carrier a phone uses at home is usually a mobile network operator, an MNO, which owns the towers and the spectrum licence behind them. A travel eSIM provider is usually the other kind, a mobile virtual network operator, buying wholesale capacity on someone else’s towers and reselling it under its own name, often blending several countries’ networks into one plan. Both are ISPs under the definition above. Neither is the box bolted to the wall at home.

## Why the ISP at home means nothing on a trip

A fixed ISP’s entire product is the wire, or the fibre, or the fixed wireless dish, that ends at one premises. Nothing about that connection ships with a traveller, and nothing about the bill paid for it at home reaches a hotel room three time zones away. The account keeps working for whoever is still in the building; it has nothing to say about anyone who has left it.

## A pocket Wi-Fi hotspot is not a workaround

A pocket Wi-Fi hotspot does not get around the split above so much as move it into a bag. It is its own small mobile ISP, a battery-powered device with a mobile data plan behind it, which puts it on the travelling side of the line rather than making it an exception to it. [Whether that box is worth carrying](https://esimradar.com/blog/pocket-wifi-vs-esim) next to a plan installed on the phone already in every pocket is a separate question, but it is a question about two mobile ISPs, not about reviving the one at home.

## Which mobile ISP to actually buy

The practical question a traveller has is not which acronym applies. It is which mobile ISP to buy from for the time away, since the fixed one at home cannot answer that at any price. The regular carrier already on the phone is a mobile ISP too, and for most people it has priced [international roaming](https://esimradar.com/blog/roaming-charges) to be avoided rather than used. A local or regional eSIM, installed before departure, is a second mobile ISP: one priced for the trip instead of for the address left behind.

Comparing those options by destination is what a mobile ISP actually costs on the ground, not what the category is called. [Compare eSIM plans for your destination](https://esimradar.com/country) to see what a local mobile ISP charges to keep a phone online for the length of the trip.

## Common questions

### Is my phone’s mobile data the same thing as my home internet?

Not the same connection, but both are ISPs under the regulatory definitions. Fixed broadband from a home ISP is wired to one address; mobile broadband is the same category of service sold over a cellular network instead, which is what a phone uses away from Wi-Fi and what a travel eSIM sells abroad.

### What is the difference between an MNO and an MVNO?

An MNO owns the towers and the spectrum licence that power a mobile network. An MVNO buys wholesale access to someone else’s network and resells it under its own name and its own prices. Most travel eSIM providers are MVNOs, which is how several brands’ customers end up sharing the same physical towers.

### Will my home Wi-Fi router work if I take it abroad?

No. A router only relays the connection its ISP wires into the building it sits in, so unplugged from that wall it has nothing left to relay. A pocket Wi-Fi hotspot is a different device with its own mobile data plan behind it, not a portable version of a home connection.

### Why does my phone show no connection when Wi-Fi is turned on?

Because having Wi-Fi turned on is not the same as being joined to a network. A phone with no saved Wi-Fi network nearby falls back to mobile data if it is available, or to nothing if it is not, so a "no connection" message with Wi-Fi on usually means checking the mobile side rather than the Wi-Fi toggle.

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