Outdated To Outstanding: July 2026's Summer Siren Trend Puts Mature Spin On Y2K Mermaidcore

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Welcome to Outdated to Outstanding, a monthly column where we discuss the trends that are clawing their way out of obscurity and back into the mainstream.

Ahead of July 2026, we're taking a look at the return of one of the Y2K era's most whimsical trends: mermaidcore. Mermaid aesthetics permeated popular culture through the 2000s thanks to series, films, and books about the fantastical creatures — think "H2O: Just Add Water" — bringing with them a wave of iridescent fabrics, fishtail skirts, flat shell beads, and nautical-themed accessories in various shades of purple, green, and blue. This maritime aesthetic re-emerged around summer 2023, becoming one of TikTok's biggest Y2K revivals, but it fell out of favor shortly after. However, three years later, we're seeing mermaidcore make its way back into the fold in an updated way.

This summer's take on the kitschy aesthetic is elevated and mature, while still holding onto the original look's lighthearted fun. Known as the "summer siren" trend, the aesthetic is characterized by light colors, sheer fabrics, and bold, expressive detailing. Think well-cut, lightweight skirts, woven handbags, beaded sandals, and chic sheer jackets. Like a less-uptight version of the quiet luxury or stealth wealth trends that have dominated the fashion world over the past few years, the siren look is all about integrating timeless pieces with dynamic materials and cool accessories.

Fun, experimental shapes and decorations have been a uniting force among the year's biggest shoe trends thus far. June 2026 saw the chunky look escape cheugy territory in the form of thick sneakers wedged flip-flops, but now we're seeing the return of beachy Y2K footwear trends like jelly sandals and beaded flip flops, but in a distinctly modern, siren-core way. 

Instead of the chunky jelly sandals that were massively popular in the 2000s, we're seeing more women reach for an updated version of the humble jelly ballet flat. The woven design of these flats is perfect for a siren look; they're a bit whimsical due to the material and color options but still feel mature and elevated at their core. Mesh jelly sandals like the Tory Burch Jelly Mary Jane Flats are a perfect example of the evolved interpretation of mermaidcore.

Like jelly sandals, beaded flip flops are another mermaidcore shoe trend getting a chic update for summer 2026. There's a wide variety of beaded sandals out there to choose from, so whether you'd prefer a more understated design like Le Monde's Grey Green Beaded Thong Sandals or a vibrant-looking Jimmy Choo Lova Mule Flat, there are many ways to get in on this trend. Beaded accents and other unique embellishments bring a playful aspect to summer footwear in a way that feels reminiscent of the original mermaidcore, while streamlined silhouettes and toned-down color schemes provide a nice touch of maturity. 

Little white dresses and white midi skirts are some of summer 2026's chicest trends for women over 50, but they also work fabulously for women of all ages who are looking to get in on the siren trend. For those who are hesitant to indulge in fun trends like mermaidcore for fear of having to revamp their entire summer wardrobe, versatile white dresses and skirts are a simple way to participate in an elevated way. Little white dresses are one of the biggest minimalist trends of summer 2026; their babydoll silhouettes and short hemlines lend themselves perfectly to the siren trend. For one, they pair excellently with the aesthetic's flat shoes. Don't believe us? Try wearing a cotton shift like the For Love & Lemons Venetia Slip Dress with woven jelly sandals to achieve an elevated mermaidcore look.

Draped high-low pieces like Reformation's Emma Maxi Skirt are already a softened version of classic mermaidcore with toned down color palettes and more delicate layers of petal-like ruffles, but they can be made even more summer-ready with a woven or beaded tote. Statement purses like Poléne's Solé handbag provide texture and dynamic movement to any modern mermaid look.

One of the cornerstones of the "summer siren" trend is glam that's both effortless and chic, and natural waves and curls perfectly fit the bill. Summer 2026 is host to a wide variety of hair-styling trends, from cropped bixie cuts to perfectly styled Old Hollywood bobs to cascading waves and thick, bouncy curls. The latter two styles give off an undeniable siren vibe and can be customized to fit many hair textures and flatter different face shapes. If you prefer a more defined cut, the soft shag may be the style for you. This cut still centers natural wave and curl patterns but includes soft layers that provide dynamic movement and emphasize volume.

Intentional styling is another a great way to integrate mermaidcore into your hair. While beach-ready waves and curls are inherently on-trend, you can further bring the sea into your hairstyle with the ultimate mermaidcore accessory: seashells. Try upgrading your hair with shell-shaped hair pins and barrettes for an extra dose of siren-like elegance. You can also dial up the summertime vibes with a versatile jewel-toned headscarf, like Donde Esteban's Formentera Silk Head Scarf.

While "clean girl" makeup is still en vogue, some of the biggest beauty trends of the summer include glowy skin and plenty of sparkle, shimmer, and vibrant colors. Reminiscent of when TikTok rejected the clean girl aesthetic in favor of the dirty girl trend, summer 2026 seems to be all about effortless glam, which is perfect for elevated mermaidcore. Jewel-toned metallic eyeshadow is a simple way to emulate the shimmery texture of the aesthetic, while still being more wearable and grown-up than just coating your lids in glitter. 

Warm-weather makeup often puts an emphasis on natural, dewy skin rather than full glam, and this can actually work to your favor in creating a "summer siren" look. Experiment with soft purple highlighters like R.E.M. Beauty's Interstellar Highlighter Topper, bringing the color from the highest point of your cheekbone up to your temple for a dramatic, siren-like flourish. Or, if that's a bit much for your day-to-day life, try a sheer iridescent lipgloss like About-Face's Light Lock Lip Gloss in the shade It's Not You It's Me. Not a big makeup fan in general? Keep your skin moisturized and glowing, and you'll look beachy all day long regardless!

When you think of what to add to your summer wardrobe, jackets probably aren't top of mind. However, for summer 2026, sheer outerwear pieces are excellent additions to any closet — and perfect for channeling an elevated mermaidcore vibe. We saw many brands, including Ralph Lauren, bring sheer organza jackets to the runway for this season, so it's no surprise that they're making an appearance off of it as well. Whether in a variety of fun colors or just plain white, sheer jackets have a playful energy that fits incredibly well in the siren trend. Gauzy pieces like the Rag & Bone Jolene Organza Jacket or Max Mara's Silk Organza Shirt have a unique, almost structured appearance, yet manage to maintain the whimsical touch that made the original mermaidcore aesthetic so appealing. 

Organza jackets are more versatile than you'd think. You can dress them up with matching bottoms or a trendy slip dress, or you can dress them down for day-to-day activities by wearing them open with a thin tank or bralette underneath. Full-length sheer organza jackets like Azalea Wang's Cassara Sheer Trench Coat are more dramatic but make excellent statement pieces that add a bit of fun to any outfit. Just remember that elevated doesn't necessarily mean stuffy and buttoned-up, so your "summer siren" look should retain the fun, whimsy, and heart that made the aesthetic so appealing around the turn of the century.