How to choose your Ocean Blues swimsuit size: three measurements and two size runs
Bust, underbust and hip, taken once with a tape, and which of the three decides each piece. What the regular run and the plus run are cut for, what a tie, a drawstring or a slider can take up, and what to do when the numbers land in two letters.
A swimsuit is the one garment you cannot try on the way you try on jeans. It has to hold when it is wet, when you lift your arms, and when you sit down on a hot bench. The letter on the tag was decided in a dry room by someone who has never seen you. So the letter is the last thing to pick, not the first. Before it come three numbers and one decision, and both take less than ten minutes with a tape measure and a mirror.
Three numbers, one tape
You need the bust, the underbust and the hip. Waist matters for a few pieces, and we will come to those, but for most swimwear the three that decide the fit are bust, underbust and hip.
Take the bust at the fullest point, with the tape level all the way round and lying flat, not pulled tight. Wear a bra that does not add shape if you wear one at all, because the swimsuit will do its own shaping. Breathe out, then read the tape.
Take the underbust directly below the bust, where a bra band sits. This is the number most people skip. It decides more Ocean Blues tops than any other, because every top with a moulded cup, a wire or an elastic band holds by the band, not by the straps. Pull the tape snug here, snugger than for the bust, since a band that measures loose will be loose in the water.
Take the hip at the widest point of the seat, feet together, tape level front and back. If you are not sure where the widest point is, move the tape down an inch at a time and take the biggest number.
Write the three down in inches. You will use them against the size chart that opens from the buy button on every piece. You will use them again next summer, too, because the numbers change less often than the letters do.
Which number decides which piece
Not every number matters for every piece, and reading the whole chart for a bikini bottom is how people end up ordering by their bra size. The table is the short version.
| Piece | Measure first | Then | Adjuster that takes up the difference |
|---|---|---|---|
| Triangle top, string ties | Bust | Underbust | Ties at neck and back |
| Halter with moulded cups | Underbust | Bust | Halter tie, sometimes a front tie |
| Bandeau or strapless top | Underbust | Bust | Back tie, or nothing |
| Wired or U-wire top | Underbust | Bust | Buckle or hook at the back |
| Bikini bottom, tie sides | Hip | Waist | Side ties or drawstring |
| Bikini bottom, sewn sides | Hip | Waist | None: the letter does it all |
| High-waisted bottom or shorts | Waist | Hip | Elastic waistband |
| Tankini top | Underbust | Bust, then torso length | Straps, if it has them |
| One-piece | Torso length | Bust, hip | Straps only |
The last column is the honest one. A tie can give you an inch or two. An elastic waistband can give you a size. A sewn side on a brief gives you nothing, and a one-piece with fixed straps gives you the straps and nothing else. The less a piece can adjust, the more the number has to be right before you order.
Two runs, not one run stretched
Ocean Blues swimwear comes in two size runs, and they are cut differently rather than being the same pattern scaled up.
The regular run starts at S. On most bikini tops and bottoms it stops at 2XL. On the athletic one-piece, the surf rash guard, the V-neck push-up tankini and the shirred bandeau one-piece it goes to 3XL. On the twist-front tankini, the shirred cut-out tankini, the ruched bandeau tankini, the 8-inch board shorts, the blouson tankini set and the long-sleeve boyleg swimsuit it goes to 4XL.
The plus run is marked with a plus sign after the letter, S+ through 4XL+, and it lives on its own pieces. The loose-fit tankini top runs the full length of it. The plus-size triangle halter top runs S+ to 3XL+, the plus-size 3-inch board shorts run L+ to 3XL+, and the plus-size high-waisted bottom runs M+ to 2XL+.
The two runs overlap in letters and differ in shape. A 2XL in the regular run and a 2XL+ in the plus run are not the same garment with a different label. The plus cut allows more through the hip and the bust for the same band, and the tankini tops in it are cut longer in the torso. So if your bust and underbust numbers are far apart, or your hip runs several inches ahead of your waist, read the plus run first. That holds even if the letter you usually buy is in the regular run.
The opposite is also true. A tall reader with a small difference between bust and underbust fits the regular run better, whatever the letter. The plus cut will have room where she has none.
What the adjusters can and cannot do
Every Ocean Blues piece with something to pull, tie or slide is listed with it, and it pays to know which kind you are getting.
**Ties.** The string-tie triangle top, the side-tie bikini bottom, the tie-back bandeau and the twist halter all fit by knot. A tie moves the band or the hip line by an inch or two either way. The triangle cups on a string slide to sit where you want them. What a tie cannot do is make a cup bigger. If the bust number is over the letter, the triangle will be too small however far apart you slide it.
**Drawstrings.** The mid-rise bikini bottom has one at each hip, and the plus-size triangle halter has one under the bust. A drawstring behaves like a tie with a stop on it: it takes up slack but does not add fabric.
**Sliders.** The blouson tankini set, the wide-strap bandeau, the retro cut-out top and the moulded-cup one-piece adjust their straps on metal or plastic sliders. A slider changes how high the cup sits on you, and on a one-piece it changes the torso length by a fraction. It does not change the band.
**Hooks and buckles.** The plus-size plunge-neck one-piece has a three-position hook-and-eye at the back, and the U-wire cut-out top has a buckle. These are the only two pieces where the band itself is adjustable after you have bought it. Everywhere else, the band is the letter.
**Removable straps.** The twist-front tankini, the ruched bandeau tankini, the shirred bandeau one-piece and the strapless twist top all come with straps you can take off. Taking the straps off changes nothing about size, but it changes what holds the top up. With the straps on, a slightly loose band is fine. With them off it is not. If you plan to wear one of these strapless, size the band snug.
Tops: the band and the cup
A bikini top or a tankini top with cups is a bra that gets wet, and it fits like one. The band does the holding, the cup does the shaping, and the straps keep the whole thing level.
Start from the underbust number and find the letter on the chart. Then check the bust number against the same letter. If both land in the same letter, order it. If the bust lands one letter above the underbust, you have a choice that depends on the cup.
On a top with a thick moulded pad, the push-up halter for instance, we say go up. The pad takes up room inside the cup, and a full bust in the smaller letter will spill over the top edge. The brand's own note on that top says the same, one size larger for a full bust.
On a top with removable pads, the string-tie triangle or the retro cut-out, take the pads out and the cup gains the room the pad was using. You can order the letter that fits the band and decide about the pads when it arrives.
On a top with sewn-in cups, the ruched bandeau tankini or the wire-free twist tankini, there is no pad to remove, so the bust number wins. Order the letter that fits the bust and use the straps or the tie to take the band in.
Bottoms: rise, hip and the tie question
A bikini bottom fits at the hip, and the rise decides where the band sits on the way there. Low-rise briefs like the Brazilian cheeky and the low-rise full-coverage brief sit on the hip bone, so the hip number is nearly the whole story. Mid-rise briefs like the drawstring bottom sit between hip bone and navel. High-waisted bottoms and all of the board shorts sit at or above the navel, and on those the waist number matters as much as the hip.
Then the tie question. A bottom with side ties, the side-tie triangle bottom or the drawstring mid-rise, forgives a hip number that lands between two letters: order the smaller and let the ties out. A bottom with sewn sides, the side cut-out bottom or the ruched-side swim bottom, does not. On those, a hip number between two letters means the larger letter. A brief that is tight at the hip rolls at the band, and once it rolls it stays rolled.
One more thing on bottoms. The fabric on a mid-rise brief with a snug waistband, the high-leg bottom for example, runs close. The note on that piece says to size up if you are between letters or fuller through the hip. We would say the same of any bottom without a tie.
One-pieces and tankinis: the torso is the number
On a one-piece the number that catches people out is the one they never measured. It is the length from the top of the shoulder, down the front, through the legs and back up to the same shoulder. A tall reader or a long-waisted one can have every other number in a medium and still find the straps of a medium cutting in. The suit is a loop, and the loop is short.
You can measure it with the tape run over one shoulder, down through the legs and back up, held snug. Compare it to the chart where the chart gives a torso figure. Where it does not, use height as a rough proxy: the taller you are, the more likely you need the next letter up on a one-piece with fixed straps. On the ones with sliders, rely on the sliders.
Tankini tops are easier, since the top and the bottom are separate and the torso length only decides where the hem falls. The twist-front tankini, the ruched bandeau tankini and the loose-fit plus tankini are all cut to reach the hip. On a long torso the hem sits at the hip bone rather than below it. That is a matter of taste, not of fit, and nothing will ride up because of it.
When the numbers land in two letters
It happens more often than not. The bust says M, the hip says L, and the chart does not have an ML. Here is the order we would settle it in.
First, look for a set that is sold as separates instead. Most of the Ocean Blues range is separates: a top in one letter and a bottom in another costs nothing extra and solves the problem for good. The sets, the high-waisted ruched bikini set and the blouson tankini set, are sized as one letter for both halves, so they are the pieces where this matters most.
Second, if it has to be one piece of fabric, go with the number that has no adjuster. On a one-piece that is the torso. On a top that is the band. On a bottom that is the hip. The adjuster takes up the other number.
Third, if there is no adjuster either, go up on anything that sits at the hip or the waist. Go by the band on anything that sits on the chest. A loose band on a bandeau will not stay up. A tight band on a brief will roll. Those two rules cover most of the pieces on this site.
The order we would do it in
Measure once, in the morning, with the tape level: bust, underbust, hip, and torso length if you are looking at a one-piece. Write the numbers in your phone. Decide which run to read by the gap between your numbers, not by the letter you usually buy. Open the chart from the buy button, find the letter for the number that has no adjuster, and check the others against it. Then order that letter, and if it arrives and the cups are the only thing wrong, try the pads out before you try the next size.
If you have done that and the piece still sits wrong, the fault is in the cut and not in your tape. The piece to look at next is the one on the same shelf with an adjuster where this one had none.
More of this sort of thing is in Swim Notes, and the Ocean Blues deck keeps the whole range one click away on the front page.