Saily is a mobile app and service that provides eSIM data plans for travelers, allowing them to connect to the internet in various countries without needing a physical SIM card. It was created by Nord Security, the same company behind NordVPN. Saily offers a user-friendly way to purchase and activate eSIMs, access data plans, and manage their connectivity while traveling, with features like automatic activation, virtual location rerouting, ad blocking, and web protection.