Notice that there are lots of mobile settings in the novel (and, no, we're not talking about phones) – the River Thames, the ocean, the cargo ship Little Bee stows away on to reach England, the train that takes her to London. These settings take on deep significance when we consider the theme of "Contrasting Regions." Characters cross a bunch of geographical boundaries, going from familiar lands to unfamiliar ones, and back again.
These geographical crossings parallel the rites of passage the characters undergo. Cleave says, "Little Bee is about two women who cross boundaries – emotional limits and international borders – that most people wouldn't cross" (source). As the characters cross back and forth between worlds, they also undergo what seems like continual processes of reinvention, adapting to the new realities they face each time.