Every character in The Light Between Oceans grieves the loss of a loved one, and this loss both compels and justifies his or her actions. The experience of loss colors different characters’ perspectives, leading sometimes to empathy and compassion and sometimes to anger.

Tom’s experiences with war enable him to understand the effects of grief and loss. Early on, grief and loss are described as forces as powerful as war that can drive people to desperate measures. Reflecting on how the despair of losing his wife destroyed his predecessor, Trimble, Tom realizes that it doesn’t “take a war to push you over that edge” (55).

Partageuse is a city that has lost many of its men to the war, which allows its citizens to overlook certain behaviors, such as the mob that drove Frank Roennfeldt to flee with his infant daughter. On Janus Rock, Isabel’s loss of three pregnancies enables her to justify her decision to keep Lucy and overrule any doubts that it is the morally right thing to do; her experiences with loss lead her to believe that she may deserve the joy that the baby brings when she washes ashore.