I’m lying on a cool slab of French granite, feeling the stress and jet lag seep out of my body as warm water poured from a pitcher glides over my skin. Through the steam, I can vaguely make out my therapist, Lina, draping leafy, dark green seaweed on my body, which feels like a cozy mermaid’s blanket. After an Atlantic sea salt scrub and pore-opening steam from the hammam, the seaweed nourishes and hydrates, leaving my skin soft and supple.

This year, The Spa at Ashford Castle in County Mayo, Ireland, earned a Five-Star Forbes Ranking, making it the only spa in Ireland to earn this accolade. And it’s well-deserved: From the moment I stepped into the neutral-hued environs, I felt as if I’d entered a sanctuary. Overlooking Lough Corrib—the largest lake within the Republic of Ireland—a tranquil relaxation pool is framed by a Tree of Life mosaic mural featuring elements of Irish and Celtic mythology, including woodland creatures and an oak tree, which provides a stunning backdrop that rivals the serene water views. “[The oak tree] is symbolizing the grounds of the Ashford estate, but for me, it’s also symbolizing or empowering the person that’s taking that moment to connect with what’s in front of them,” says Michelle Ryan, director of spa and wellness at Ashford Castle.

Beyond its captivating scenery, The Spa at Ashford stands apart with its signature hammam treatments, including The ‘Scrub’ Seaweed Experience, which has become one of the most popular treatments on offer at the spa. “I love to see what’s unique and different out there, but always having that focus of what’s the result—what is the guest getting from this treatment,” Ryan says. “I want it to be functional, I want them to feel the benefits.”

Ryan has always believed in the benefits of seaweed—which include purifying the skin with natural antioxidants and helping to improve its suppleness and elasticity—as well as its efficacy in treatments. Thanks to her history working at VOYA, a premier organic seaweed-based Irish skincare brand, she gained valuable experience teaching, training and developing products and treatments. At The Spa at Ashford, Ryan says she wanted to create something “identifiable to us” that utilized a traditional Irish ingredient: seaweed.

“All of the seaweed that we work with is hand-harvested from the Irish coastline, and ethically harvested, also,” Ryan says, explaining that only the top third of the plant is harvested so that it can regrow and replenish itself. The seaweed used in the treatments goes into compost, and gardeners use it for the polytunnels—greenhouses that shelter vegetables grown on-property.

I experienced The Purification Journey—new to the menu in July—which begins with an internal cleanse via a VOYA seaweed-infused tea, with a choice of chamomile, peppermint or fennel. In the hammam, a soapy body cleanse called Squeaky Clean features a blend of essential oils: lemon, lime, clove, basil, mandarin and patchouli. Then Atlantic sea salt, combined with angelicus serratus (seaweed oil), exfoliates and hydrates. Large seaweed fronds, fuccus serratus (seaweed wrack), are draped over the body, which are “great for stimulating the collagen of the body, so the appearance of your skin tone will visually look hydrated, much more toned,” Ryan says. The body is cleansed with hot and cold water alternately throughout the treatment, which stimulates the lymphatic system. The treatment finishes with Softly Does It, a body moisturizer with Shea butter, aloe and seaweed.

When I reluctantly emerged from the hammam, I felt like a new person. Or at least a better version of myself—with silky-smooth skin. ashfordcastle.com