In the photos, Kruger, 41, wore a black, one-piece bathing suit with an open back that showed off her toned figure as she sat on the sand and took a dip in the water.
Her partner, 48, hit the water wearing a full wet suit and surfed the Costa Rican waves while she looked on from the shore.
The couple have been maintaining a long-distance relationship because of their demanding work schedules. The Walking Dead star has been busy filming the AMC zombie hit in Atlanta, Georgia, while the German actress was shooting JT Leroy in Canada, so a romantic getaway in Central America served as the perfect place to reunite.
Reedus and Kruger met when they costarred in the 2015 movie Sky, and were spotted showing major PDA in March when they were seen kissing in New York City after leaving his place in the East Village.
The relationship is the first for the actress after splitting with her boyfriend of 10 years, Joshua Jackson, in July 2016. Reedus has a son, Mingus, with supermodel Helena Christensen and was previously linked to Courtney Love and Walking Dead costars Laurie Holden and Emily Kinney.
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