Mobile data plans are agreements with cellular service providers that allow users to access the internet on their smartphones and other mobile devices. These plans typically come with a set amount of data, measured in gigabytes (GB), which determines how much online activity you can do, such as browsing websites, streaming videos, or using social media. There are different types of mobile data plans, including prepaid and postpaid options. Prepaid plans let you pay in advance for a specific amount of data, while postpaid plans charge you at the end of the month based on your usage. Choosing the right plan depends on your internet habits and budget.