Inventory management for Shopify swimwear brands

The inventory problems swimwear brands run into

• Size curve imbalance. A bikini style might sell mostly in S and M, with XS and XL moving much slower, so treating all sizes as one SKU hides stockouts in the popular middle sizes.
• Color and print churn. Prints often change season to season, so last year's sales history for a print is not a reliable guide for a new print even in the same silhouette.
• Mix-and-match separates. Tops and bottoms are often sold as separate SKUs but bought together by customers, so running out of one half of a popular pairing effectively stops both from selling.
• Fabric and trim MOQs. Suppliers may hold minimums on cut-and-sew runs per colorway, which forces you to commit to a full case pack across sizes even if only a few sizes are proven sellers.
• Short, sharp selling window. Most swimwear brands sell the bulk of a style in a narrow window before summer, so arriving a few weeks late to stock can mean missing most of the season's demand.

Seasonality and demand

Swimwear demand is sharply seasonal. In the northern hemisphere, most brands see a ramp from early spring through midsummer, with a smaller secondary bump around resort and holiday travel season in December and January. The core risk is that you place orders with overseas suppliers months before the selling window opens, based on a forecast of what will sell, not what has already sold. If you undercommit, you run out of the best sizes and colors right when demand peaks and cannot reorder in time. If you overcommit, you are left holding end-of-season inventory that only moves at a discount. Plan your main order-by dates around when your supplier's lead time plus your desired safety stock pushes back from the start of your peak selling weeks, not from the calendar date you want stock to arrive.

Suppliers, lead times and minimums

Swimwear brands typically work with cut-and-sew manufacturers overseas, often in Asia or Central America, plus sometimes a domestic cut-and-sew shop for small runs or samples. Overseas suppliers often take several weeks for production plus shipping time, and MOQs are commonly set per colorway or per fabric roll rather than per style, which can force you into a full size run even if you only want more of your best-selling sizes. Domestic suppliers tend to have shorter lead times and lower minimums but higher per-unit cost.

Worked example

Say you sell a one-piece swimsuit in size M, Black, and it sells 5 units a day in peak season. Your supplier's lead time is 20 days, and you keep 5 safety days as a buffer. Reorder point = 5 x (20 + 5) = 125 units. If you want 30 days of cover and you currently hold 60 units with 40 already on order, order quantity = 5 x (20 + 30) - (60 + 40) = 250 - 100 = 150 units. SteadyShelf would round that 150 up to the nearest case pack your supplier allows, say 160 if packs come in 40s.

Try it with your own numbers in the reorder point calculator, or size your buffer with the safety stock calculator.

A simple system to start this week

1. List every size and color combination as its own variant in Shopify, not just the style.
2. Enter each supplier's case pack size and minimum order quantity so suggested orders round up correctly.
3. Set lead times generously for overseas cut-and-sew suppliers, including shipping time, not just production time.
4. Review the weekly reorder email in the eight to ten weeks before your peak season starts, not during it.
5. Track fabric or dye lot differences manually outside SteadyShelf if a reprint needs to match an earlier batch.
6. Approve purchase orders early enough that the order-by date still leaves room for a supplier delay.

How SteadyShelf fits swimwear brands

SteadyShelf forecasts per variant, so it treats each size and color as its own line and gives you a separate order-by date and quantity for each. This matters for swimwear because size curves are rarely even. It will not track fabric lot or dye batch matching, and it does not handle transfers if you stock both a warehouse and a retail location, so you will need a separate process for those.

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