Customization Options

Q: Can pouch capacity be increased?

Yes. You may request a small pouch adjustment such as Pouch +1cm ×2 to increase the depth and overall capacity. Some styles can be adjusted up to +2cm ×2.

Calvin Lin
2009/11/18 (updated: 2026/07/19)

From sexy to playful, looking for something different?

Back Cuts

Since 2017, styles with a 4th code digit of 1, 3, 5, or 7 often offer optional back piece changes.
For example, H1 can be switched to T1 (no extra charge), or to Y1 (extra charge applies).
These changes are selectable during ordering and are not part of full custom tailoring.
New designs from 2017 onward are not compatible with older designs from 2009–2016, so back cuts such as B1, H1, or Y1 cannot be applied to earlier styles.
We offer a variety of back styles, ranging from sexy to playful. Each back type is available in four waist heights. For Y-style thongs, the heights are: Y0 — low rise, Y1 — super-low rise, Y2 — ultra-low rise, and Y3 — extreme-low rise. Y1 is the most common default height.

💡 For details, see: Minor Custom Tweaks

Adjusting Waist Measurement

iSwim underwear comes in three size ranges: M to XL. Swimwear is designed for active swimming use and comes in five size ranges: S to XXL. Swimwear generally runs slightly smaller at the waist than underwear because it is designed for longer periods of use in water.
For underwear, if your body size is between two sizes, such as between M and L, you may order M and note Waist +1cm ×2 in the product note. If you prefer a slightly higher back piece, you may order L and note Waist -1cm ×2.
For swimwear, waist adjustment is available below the smallest size S and above the largest size XXL. The standard adjustment range is 1cm ×2.
For both underwear and swimwear, if the largest size still feels tight, you may note Waist +1cm ×2. The maximum standard adjustment is Waist +2cm ×2; larger adjustments may require an additional charge.

💡 For details, see: Minor Custom Tweaks

Adjusting Pouch Capacity

iSwim designs focus on both comfort and sexiness. Pouch volume remains relatively consistent between sizes, while the main differences are usually the waist measurement and overall rise. For some styles, the front height of size L has been the same as size M since 2017.
If you have worn the same style before and feel that the pouch is slightly tight, or if you need more front space, you may note Pouch +1cm ×2 in the product note. We will increase the pouch depth and overall capacity. Some styles can be adjusted up to +2cm ×2.

💡 For details, see: Minor Custom Tweaks

Material Change Requests

Most styles from 2017 onward are designed with specific fabrics and colors. To request a change, please choose “Other fabric/color” if that option is available, and indicate the material and color code in the product note.
Available fabric options depend on the pattern, waistband, and construction of each style. Please refer to the options shown on the product page, or contact us if you are unsure whether a specific fabric can be used.

💡 Underwear made with swimwear fabric:
Most underwear styles, including many 8mm strap styles, can now be made with suitable swimwear fabric. A small number of special styles may not be compatible due to pattern, construction, or material limitations.
The sizing will still follow the original underwear pattern and will not be changed to swimwear sizing or construction.
A base handling fee of NT$350 (or 50% of the store price, whichever is higher) will apply.
Additional changes, such as back cut adjustments, ruching, or color mixing, may require an additional charge.

💡 Note: Some special styles may not be available in swimwear fabric. Final availability depends on the product structure and compatible materials.

💡 Note: Swimwear styles cannot be converted to underwear due to differences in pattern construction and waistband design.

Customization FAQ

Can iSwim products use a different back cut?

Many styles introduced from 2017 onward can use compatible back cuts. Some changes are available at no extra charge, while others may require an additional fee. Older styles from 2009–2016 are not compatible with the newer back piece system.

Can the waist be adjusted if I am between two sizes?

Yes. Some underwear styles can be adjusted by approximately 1cm ×2 at the waist. If the largest size is still too tight, some styles can be increased up to +2cm ×2. Adjustments beyond the standard range may require an additional charge.

Can pouch capacity be increased?

Yes. You may request a small pouch adjustment such as Pouch +1cm ×2 to increase the depth and overall capacity. Some styles can be adjusted up to +2cm ×2.

Can I change the original fabric or color?

Some products allow other available fabrics or colors. If the product page offers an “Other fabric/color” option, select it and enter the material and color code in the product note. Availability still depends on the product pattern and construction.

Can 8mm strap underwear be made with swimwear fabric?

Yes, in most cases. Many 8mm strap underwear styles can now be made with suitable swimwear fabric, although a small number of special styles may not be compatible because of pattern, construction, or material limitations.

Does underwear made with swimwear fabric become a swimwear pattern?

No. The product will still be made using the original underwear pattern and size specifications. Only the compatible fabric is changed.

Is there an extra fee for making underwear with swimwear fabric?

Yes. The base handling fee is NT$350 or 50% of the store price, whichever is higher. Additional modifications such as back cut changes, ruching, or color mixing may require extra charges.

Can a swimwear style be converted into underwear?

No. Swimwear styles cannot be converted into underwear because their pattern construction and waistband design are different.

※Customization options will be updated on this page whenever services or conditions change. Last updated: July 15, 2026.