The Breaking Wave by Katherine Hayton

After their daughter is ripped from them by the Boxing Day Tsunami, Christine and Gary Emmett hunt through Phuket, Thailand, trying with increasing desperation to find Tamsin; or find her body. When a village contact reaches out to say he's found Tamsin, alive, they make a journey. A journey that could see them reconnect with their lost daughter or face the truth that she's lost to them, forever.