The High Note actress, 31, was spotted soaking up the sun with the Coldplay frontman, 44, during a boat ride off the coast of Mallorca, Spain, on Wednesday. They later walked arm-in-arm around the resort town of Palma, in the Balearic Islands.
They enjoyed an escape from their slice of Malibu, Martin's $12.5 million mansion where they've been living together since he purchased the home in October. A source told PEOPLE in February that Johnson, who previously lived in the Hollywood Hills, "seemed like more of a city girl" before they began dating.
"She seems to enjoy [Malibu] as much as Chris does," the source explained to PEOPLE. "They both love the outdoors and often take beach strolls. They also support local restaurants."
Johnson and Martin have been known to spend Sunday dinners with his ex-wife Gwyneth Paltrow, 48, and their children Apple, 17, and Moses, 15, as well as Paltrow's husband Brad Falchuk, 50, and his kids Isabella and Brody. "It's obvious that everyone still gets along great," the insider added.
The Fifty Shades of Grey actress sparked engagement rumors back in December when she was spotted wearing a green ring on her ring finger. However, Johnson and Martin's reps did not respond to PEOPLE's request for comment.
They've been romantically linked since October 2017 when they were spotted on a sushi date in Los Angeles. A source told PEOPLE in April 2019 that the couple was "pretty serious." The insider added: "They are very low-key together. They usually have friends over and rarely go out."
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Johnson has recently been filming her upcoming movie Persuasion, based on Jane Austen's final novel of the same name. She plays heroine Anne Elliot, who must confront her past when her path crosses with her lost love, Captain Frederick Wentworth. Johnson stars alongside Henry Golding and Cosmo Jarvis in the Netflix film, which premieres in 2022.