For activity-based risk assessment of open Wi-Fi networks, an activity occurring at a consumer application is analyzed to determine that a connection with a first open Wi-Fi network is to be used in conjunction with the activity. From an entry representing the activity in a risk profile, a risk level of the activity is selected. Whether an overall risk value of the first network exceeds the risk level of the activity is determined. When the overall risk value of the first network exceeds the risk level of the activity, the connection with the first network is terminated. A second open Wi-Fi network with a second overall risk value that does not exceed the risk level of the activity is selected. A second connection with the second network is established. The activity is allowed to proceed using the second connection with the second network.