Using the Keikyu Main Line to get to Narita Airport. Do i need to buy any additional ticket or is the Suica Card just fine?

Just planning ahead for my family as we are currently staying around Kamata (yes I understand Haneda is right there lol. Don't ask)

The Keikyu Main Line from Kamata to Narita is the most straightforward and simple with no transfers. I'm wondering if there are any tickets or bookings I have to keep in mind or is the balance in the Suica card enough?