Swimwear and beachwear retail combines fashion apparel complexity (size variants, colour photography, seasonal collections) with specific functional requirements (UV protection, chlorine resistance, material performance) and unique sizing conventions (cup sizing for women's swimwear, separate top and bottom sizing). The sustainable swimwear segment has also grown significantly — recycled nylon (ECONYL) and recycled polyester from ocean plastic are now standard for premium brands. WooCommerce stores in this space typically had custom fields for material composition and UV rating, plus complex sizing variants that benefit from Shopify's structured approach.

Product categories

Women's swimwear: One-piece swimsuits, bikinis (separates), tankinis, swimdresses
Men's swimwear: Board shorts, swim trunks, swim briefs, rash vests
Children's swimwear: UV protection suits, float suits, armbands
Cover-ups and beachwear: Kaftans, sarongs, beach dresses, hoodies
Surf apparel: Wetsuits, boardshorts, rash guards, surf leggings
Accessories: Swim caps, goggles, beach bags, flip flops
UV protective clothing: UPF-rated long-sleeve rash vests, UV hats, UV swim shirts for children

Sizing conventions in swimwear

Women's swimwear sizing

UK numerical sizes (8, 10, 12, 14, 16) — standard across one-pieces and bikini sets
XS/S/M/L/XL — alternative sizing for many brands
Cup sizing for bikini tops: separate the sizing by top and bottom — this is the critical decision
Bikini separates: Sell tops and bottoms as separate products with independent sizing. This dramatically reduces exchange rates (customer can buy size 10 top, size 12 bottom). Top has Size (8–16) + Cup (A/B/C/D/DD/E) variants. Bottom has Size (8–18) variant.
Bikini sets: If selling as a set, either: (a) standard UK size set with note "top runs one cup size larger", or (b) use "Top Size + Bottom Size" dual variant approach.
International size guide: many swimwear customers are international (or purchase as holiday gifts). Always include UK, EU, and US size equivalents on your size guide page.

Children's swimwear sizing

Age-based (18–24m, 2–3y, etc.) AND height-based (86cm, 92cm) — use dual labels as with children's clothing
UV suits: size for sun protection is critical — a suit that's too loose doesn't provide rated UV protection

Wetsuits

Wetsuit sizing: height + weight grid (e.g., Tall S, Short M, Regular M) — use variant option with size codes
Thickness: "3/2mm", "4/3mm", "5/4/3mm" — use separate variant option for thickness, or separate products by thickness

UV protection metafields

product.metafields.swimwear.upf_rating (number_integer) — Ultraviolet Protection Factor: UPF 15, 30, 50, 50+
product.metafields.swimwear.uv_protection_level (single_line_text) — "Good (UPF 15–24)", "Very Good (UPF 25–39)", "Excellent (UPF 40–50+)"
product.metafields.swimwear.uv_certification (single_line_text) — "EN 13758-1 certified", "OEKO-TEX UV Standard 801"
Display UPF rating prominently — particularly for children's UV swimwear where parents specifically shop by UPF rating. A "UPF 50+ Certified" badge is a significant conversion driver for this segment.

Swimwear material metafields

product.metafields.swimwear.fabric_composition (single_line_text) — "80% Nylon, 20% Elastane", "78% ECONYL recycled nylon, 22% Xtra Life Lycra"
product.metafields.swimwear.recycled_material (boolean) — made from recycled materials
product.metafields.swimwear.recycled_material_pct (number_integer) — percentage recycled content
product.metafields.swimwear.chlorine_resistant (boolean) — chlorine-resistant fabric (important for regular pool use vs beach use)
product.metafields.swimwear.quick_dry (boolean)
product.metafields.swimwear.lining (single_line_text) — "Fully lined", "Unlined", "Removable lining"
product.metafields.swimwear.care_instructions (single_line_text) — "Rinse in cold water after sea/pool use, hand wash"

Sustainable swimwear content

The sustainable swimwear market is growing rapidly — brands using ECONYL, recycled ocean plastic, or other eco materials should structure this data properly:

ECONYL recycled nylon: regenerated nylon from fishing nets, fabric scraps, and industrial plastic waste. Display as both a sustainability claim and a premium material credential.
Recycled polyester (rPET): from post-consumer plastic bottles. Standard in surf apparel and rash guards.
Bluesign certified: fabric produced with reduced water, energy, and chemical use. Use metafield to store certification.
Brand-level sustainability credentials: carbon-neutral brand, certified B Corp, 1% for the Planet — display as shop metafields alongside product-level material information.

Seasonal inventory management

Swimwear is highly seasonal — UK peak is April–July for domestic, plus year-round for holiday destinations
Collection naming: "Summer 2026 Collection", "Resort Collection" — create seasonal Shopify collections with automated rules (tag: summer-2026)
Pre-season: launch new collection pre-order in February/March for summer delivery
End-of-season sale: automatic discount on previous season stock from August onwards
Carry-forward vs clearance: decision per product — some styles carry forward season-to-season (classics), others are retired. Tag accordingly: classic vs seasonal
Google Shopping: ensure seasonal products have updated availability status — "out of stock" for discontinued styles rather than keeping them live at zero inventory

Swimwear migration checklist

Decide on bikini top/bottom strategy: separates vs sets (separates recommended for size flexibility)
Set up women's swimwear size + cup variant for bikini tops
Set up children's swimwear dual sizing (age + height)
Create swimwear metafield namespace: upf_rating, fabric_composition, chlorine_resistant, recycled_material, lining
Migrate UV protection and material data from WooCommerce custom fields to metafields
Display UPF badge prominently on UV-rated product pages
Create international size guide page (UK, EU, US conversions)
Set up seasonal collection structure for Summer 2026 launch
Configure Google Shopping attributes: gender, age_group, colour, size — required for apparel
Add care instructions metafield (rinse/wash after sea/pool use — important for customer satisfaction)
Test: bikini top size variant (size 10 / cup B) → correct SKU → correct price
Test: UPF rating displays correctly on children's UV swimwear product pages

The decision to sell bikini tops and bottoms as separates rather than fixed sets is the highest-impact structural decision for a women's swimwear store, and the migration is the ideal moment to make it. A WooCommerce store that sold sets (size 10 set — top and bottom together) had customers constantly returning because a size 10 top with D cup didn't work for them. Moving to separates eliminates that entire return category. Yes, it creates more SKUs and more product pages — but each additional product page targets additional search queries ("bikini top size 10 D cup UK"), and the reduction in returns more than offsets the management overhead. Many women's swimwear brands that made this switch on migration reported returns dropping by 30–50% in the first season.

Migrating a swimwear & beachwear store from WooCommerce to Shopify (2026)