I noticed that there weren't any tabs for this song so I thought I might tab it out.
pretty easy. Here's the basic melody.
[ Tab from: https://www.guitartabs.cc/tabs/k/keane/atlantic_tab.html ]
e|---------------------------------------------------------------------------------------------------|
B|------4--------4--------4--------4--------5--------5--------5--------5--------3--------3--------3--|
G|---3--------3--------3--------3--------3--------3--------3--------3--------3--------3--------3-----|
D|6--------6--------6--------6--------6--------6--------6--------6--------6--------6--------6--------|
A|---------------------------------------------------------------------------------------------------|
E|---------------------------------------------------------------------------------------------------|
|---------------------------------------------------------|
|------3--------4--------4--------4--------4--------4-----|
|---3--------3--------3--------3--------3--------3--------|
|6--------6--------6--------6--------6--------6-----------|
|---------------------------------------------------------|
|---------------------------------------------------------|