On the face of it, 3G and Wi-Fi are just two different ways of wirelessly connecting to the internet. However, the differences between the two can be quite confusing so SilverExplorers are here to guide you through them.
3G just stands for Third Generation. It is the third generation of mobile telecommunication networks. Mobile networks, which are what allow you to call from your mobile phone whilst you are out and about, have been around for a while. The first generation (or 1G) of mobile networks only allowed you to use the network for phone calls and texts, but they have since been updated and developed to allow you to access the internet through the network. This is what 3G refers to, allowing you to access the internet through these new and updated mobile phone networks.
For those of you who have heard of 4G, this is just the next generation which is coming into place at the moment. It is essentially just a faster version of 3G.
Wi-Fi (a play on the term Hi-Fi)* is another way of wirelessly connecting to the internet. Wi-Fi is broadcast locally, as opposed to nationally like 3G networks. A Wi-Fi network is available within a range of a few meters of the specific device (known as a router) broadcasting it. Many people have their own wireless networks within their house, and they are often also found within cafes, restaurants and other public places. Generally with a wireless network you need to have a specific password to be allowed access to the network. This is not the case with 3G.
It is worth noting that places that have Wi-Fi available are known as Wi-Fi Hotspots or just Hotspots.
*Technically Wi-Fi is a trademarked name for a Wireless Local Area Network (WLAN) that complies to certain standards. However, it is synonymous with any wireless network in common parlance.
Another way to picture it
A good way to imagine the difference between the two is traditional phones. In your house you might have a wireless handset which you can use within the house but if you go out of range of the base station then it will cut out. You cannot go into town with your wireless handset. This is like Wi-Fi
On your mobile phone however, you do not need to be close to your own particular base station, but anywhere within the range of a signal mast. This is like 3G.
In broad brush strokes Wi-Fi is generally free at the point of use whereas 3G is not. However, this is most certainly not a catch all definition as the cost relies on a number of factors (whether you have a contract, data usage, whether there are usage limits etc.) so if in any doubt it is certainly best to contact your network provider or the person operating the Wi-Fi network to check.
For more information about mobile internet check out Mobile Data – Explained