Ipswich Swimsuit


Size Size guide

Pattern format

Soak up the sun in the Ipswich Swimsuit, an underwired swimsuit sewing pattern designed for big boobs in cup sizes C–H!

This modern pattern has two cleverly color-blocked variations: a one-piece swimsuit with a contrast waistband or a high-waisted bikini with piping detail. Both suits feature supportive straps, and an optional underwired foam swim bra and boning, so that you're comfortable lounging by the pool or playing volleyball on your favorite beach. Mix prints and colors for a swimsuit that celebrates your body and your creativity, and keeps you feeling secure all summer long.

This Cashmerette pattern includes:

  • Cup sizes from C to H
  • A sizing calculator which will tell you exactly which size to make
  • A beautifully illustrated and detailed instruction booklet, to guide you no matter your sewing level

Want step-by-step help making your Ipswich? Check out our online workshop “Swimsuit Making for Curves” where Jenny Rushmore will take you through the whole process with confidence!

Interested in making a tankini version of the Ipswich Swimsuit? A free expansion pack is available here

Want to see how this pattern will look on you? Sketch your plans on a body outline croquis that's custom made to your measurements with MyBodyModel. Learn more » 

Product information




12 to 32, in three cup sizes (C/D, E/F, G/H). Includes 40-62” bust and 42-62” hip. Find your size in seconds using our size calculator.


Swimsuit lycra/spandex, with 4-way stretch (at least 50% in both directions), swimsuit lining with 4-way stretch (at least 50% in both directional), optional contrast swimsuit/spandex for piping (View B). 


All Views

  • Stretch needle, polyester thread
View A (One-piece)
  • 5 yards (4.5 m) of ¼” – ⅜” (0.6 – 1 cm) rubber/swimwear elastic
  • 2 yards (1.8 m) of ½” – ⅝” (1.25 – 1.5 cm) bra strapping (or firm elastic)
  • 1 swimwear closure or S Hook (1” / 2.5 cm)

View B (Bikini)

  • 6 yards (5.5 m) of ¼” –⅜” (0.6 – 1 cm) rubber/swimwear elastic
  • 2 yards (1.8 m) of ½” – ⅝” (1.25 – 1.5 cm) bra strapping (or firm elastic)
  • 2 swimwear closures or S Hooks (1” / 2.5 cm)

Optional Swim Bra

  • 1 yard (0.9 m) of ⅝” (1.5 cm) wide Fold Over Elastic
  • 1 yard (0.9 m) of ¼” (6 mm) stay tape
  • ⅜ yard (35 cm) swim cup foam (45” / 115 cm wide)
  • ¼ yd (15 cm) of stable bra lining, like Duoplex (45” / 115 cm wide)
  • ⅜ yard (35 cm) of power mesh (45” / 115 cm wide)
  • 1 yard (0.9 m) of underwire channeling
  • 1 set of regular length underwires (coated steel or plastic)

Optional boning: 

  • ⅓ yard (28 cm) of pre-covered ¼” (6 mm) plastic boning, or ⅓ yard (28 cm) plastic boning plus ⅓ yard (28 cm) channeling.

Customer Reviews

Based on 18 reviews
It's definitely worth the trouble

To be fair, I've only been sewing for a year and never finished a Cashmerette patterns for advanced sewists before. Only (confident) beginner. My friend told me to get the course and that was definitely helpful but I feel I've been going from the instructions to the tutorial and back a LOT. Especially for me toile, I had to do a lot of seamripping because it's really really easy to get a pattern piece upside down.

But... in the end, I made a swimsuit, for the first time ever. And also for the first time ever, it fits great. I'm tall so I'm used to stretching the fabric of store-bought swimsuits to the max but with this pattern, I just add 5cm at the top and 5cm at the bottom and there's no stretch! Amazing!
So I would recommend the pattern but if you're like me, get the course as well because it's so much easier to see it done than to just guess from the instructions.

Suzanne Wall
I didn’t think I could do it!!

The swimsuit turned out greatI Highly recommend the tutorial, Jenny does a great a job with the instructions and it’s nice to see the actual making of it. I will be making more!!

Nice swimsuit

Overall thus is a very good pattern. I love the style converted to a tankini.. I did have problems with the swim bra, but I am very disproportionate with large breaststroke and smaller shoulders. The Willodale bra fit in perfectly to resolve the issue for me. Easy to sew. The only directions I was confused by were the straps. Customer service was great at answering questions and offering solutions.

Great support with the swim bra

I made my Ipswich with the built in swim bra. I also added some extra power mesh in the lower front which was not part of the design. With a little tweaking the swim bra fit well and was supportive. I did find my spandex straps needed extra strengthening so I inserted bra strapping inside and this stopped them stretching too much. I made a size 18G . It’s a complex pattern and needs carefull reading of the instructions. I also advise you label the side panel upper and lower front and back pieces as they are easily confused for each other! I used swim spandex and Maxilock stretch thread from Boodesigns. Bra cup foam, underwires and casing from Boobytraps, both companies in Australia. I made a test run pair from some second hand spandex leggings to save money!

Most technical sew I’ve done!

I just finished my Ipswich, following along with Jenny’s online course. Wow, I learned so much! Making the inner bra was actually not difficult at all and I much prefer a bra to just a shelf bra. I highly recommend taking the class if you’re new to sewing bras or to sewing swim. My only wish is that there were some alternatives to the neckline. I’ll lose my next one by about 3”. My bust sits quite high, so the top of the bathing suit is almost at my neck. I lowered slightly with some ruching.

Mary Powell
Quite a journey

This suit looks amazing once finished, but it was neither quick nor easy. The first challenge was fitting. While adequate instructions were provided for blending sizes for the waist and hip, no guidance was given for fitting bust. I normally make a do a full bust adjustment on Cashmerette's G/H cups and had no idea how to manage that with the built in bra. Jenny did provide a suggestion (to size up and then shorten the neckband and straps) once I emailed, but it would have been nice to have that included in the pattern. Second, there are at least three types of elastic used in the suit, FOE, swim, and strap, yet most of the time the instructions just say "elastic." After reading through the instructions multiple times, I concluded that swim elastic was meant whenever simply "elastic" was written. It turned out fine, so I hope it was right. Again, something extremely simple for the pattern writer to include clarification of. Lastly, the straps were a nightmare to attach. It would have been helpful to know whether the folded strap "sandwich" was meant to be flush with the edge of the suit (sewn at 5/8th seam allowance), or sewn at 3/8ths like the rest of the suit. I sewed at 5/8ths so that the end of the back band (part 15) looked as much like the picture as possible. Again, a few sentences of clarification would have saved a lot of struggle and half a bottle of wine.
All in all, the finished suit looks great. Subsequent suits will be easier, but oh boy did I almost give up.