Saturday 3 February 2024

Forsite Under the Sea Max Adult Diaper Review

 *For more information on how I do reviews see Diaper Test Methodology



The Forsite Under the Sea is a high absorbency diaper produced for Forsite Health Canada. It joins the Forsite AM/PM and Forsite Euro Max as a distinct line of product by the company, but largely resembles the AM/PM in construction. While the Forsite AM/PM has more of a medical feel to it, this diaper seems more geared toward the ABDL community as it features a playful sea-themed backsheet pattern and doesn’t contain a wetness indicator. The advertised absorbency also runs a bit ahead of the AM/PM, but in reality I found absorbency to be more dependent on moisture channeling than padding capacity in these diapers.

During testing, I found this diaper to be better suited for bedwetting than during dailywear. It has enough absorbency to be used in either case, but because of the way the padding channels moisture you’re more likely to get better capacity value out of it when lying down than when seated or where the diaper is otherwise compressed between your legs. This is because the padding runs quite wide and has a strong tendency to fold inward so it will direct moisture toward the edges. In reality I found it should be safe to absorb at least 2~3 wettings before leakage would be a concern. From a pricing perspective it runs very high, right up there with many of the most expensive premium diapers. It’s a little more expensive than the Forsite AM/PM so it does feel like there’s a bit of a premium on the prints and it’s not likely to be economical for daily wear. That said, the prints are quite unique/attractive and I can certainly see the appeal. I’d like to say a special thanks to Corry for recommending the Forsite Under the Sea for review and contributing a donation to help support it!

Key Features:

  • Plastic backsheet
  • Landing zone
  • Repositionable tapes
  • Standing inner leak barriers
  • Blue sea-themed backsheet


  • Strong tapes
  • High absorbency
  • Extensive padding
  • Comfortable and durable


  • Inefficient moisture direct to rear padding
  • Limited sizing
  • High unit cost

Product Details

For the purpose of this post I will be reviewing and referring to the medium-sized Forsite Under the Sea Max Briefs Diaper. However, other available sizes are listed below:


Brand: Forsite Health (by Forsite Health Inc.)
Manufacturer: Weifang Mimosa Personalcare Technology
Origin: China
Units Per Bag: 10
Cost Per Unit: $$$$
Dimensions (L x W x H): 34 cm (13.4") x 19 cm (7.5") x 24 cm (9.5")
Weight: 2.3 kg (5 lbs)
Available Sizes: M, L
Advertised Absorbency: Maximum (4980 ml)

1.1 Forsite Under the Sea Packaging


Backsheet: Plastic (poly)
Wetness Indicator: No
Standing Inner Leak Guards: Yes
Leg Gathers: Yes
Product Style: Tab-Style Brief
Refastenable Tabs: Yes
Number of Tapes: 2
Repositionable Tabs: Yes
Outer Color: Light blue (playful sea theme)
Inner Color: White (light blue rectangle in the middle)
Front Waistband: Yes
Rear Waistband: Yes
Folded Thickness: 3.7 cm (1.4")
Folded Length: 23 cm (9.1")
Dry Weight: 217 g (7.7 oz)
Fragrance: No
Diaper Dimensions (L x fW x mW x bW): 82 cm (32.3") x 65 cm (25.6") x 33 cm (13") x 62 cm (24.4")
Wing Shape (Front, Rear): Rectangular, Rectangular
Padding Dimensions (L x fW x mW x bW): 68 cm (26.8") x 31 cm (12.2") x 21 cm (8.3") x 40 cm (15.8")
Padding Wing Dimensions (fPW x fPH x bPW x bPH): 5 cm (2") x 15 cm (5.9") x 9.5 cm (3.7") x 22 cm (8.7")
Padding Wing Shape (Front, Rear): Semicircle, Semicircle
Total Padding Area: 1996 cm2 (309 in2)
Tape Spacing (t1 x t2): 3 cm (1.2") x 13 cm (5.1")
Tape (W x L): 4 cm (1.6") x 4 cm (1.6")

1.2 Forsite Under the Sea Diaper

Laboratory Absorbency Tests

Total Absorption Volume (after press out): 2283 ml (80.5 oz)
Total Absorption Volume (before press out): 2458 ml (86.7 oz)
Time to Absorb Wettings (first to last): (51 s, 49 s, 58 s, 63 s, 66 s, 74 s, 70 s, 82 s, 93 s, 87 s)
Wet Folded Thickness: 8 cm (3.2")
Used to Total Padding Ratio: 84%
Total Padding to Absorbency Ratio: 1.14 ml / cm2 (0.26 oz / in2)
Press Out Volume: 175 ml (6.2 oz)

Surface Dampness Rating: 4

The Forsite Under the Sea padding is very similar to the Forsite AM/PM padding and both showed early surface dampness during the lab test. In this case significant dampness showed up as early as the second wetting. This puts it well behind the better performers in this category like the BetterDry or Seni Super Quatro. Even so, it didn’t feel overly damp during real world testing as the extensive padding coverage allows better moisture distribution and reduces the impact of excessive dampness.

2.1 Wet vs Dry Diaper After Capacity Test

2.2 Used vs Unused Padding After Capacity Test

"Real World" Absorbency Tests

Posture Tests


Total Absorbed Volume: 1308 ml (46.1 oz)
Total Wettings: (1 standing, 2 sitting)
Leaked After Sitting: No
Used to Total Padding Ratio: 63%
Padding to Absorbency Score: 0.66 ml / cm2 (0.15 oz / in2)

Standing-Sitting Rating: 8
The Forsite Under the Sea demonstrated strong performance when tested while standing and sitting. The first wetting while standing was quickly wicked through the padding. I believe the wide mid-section padding was key here as any pooling quickly distributed to dry regions of padding. Afterward there was still considerable dry padding at the front and rear and it didn’t really feel any different from its dry state. Upon sitting shortly afterward there was no sign of leakage or pressout. On the second wetting while seated, moisture quickly pushed up front padding in the diaper with very little making it to the rear padding. There was some brief pooling but otherwise it was absorbed quickly and felt reasonably dry once absorbed. The padding swelled quite a bit at this point so there may have been a bit of a “dam” effect. On the third wetting that effect became apparent. Moisture quickly pushed up and pooled at the front of the diaper then crossed the leak guards and channeled under the wings. Surprisingly it didn’t actually leak out from the wings and was absorbed into the rear padding at the opposite end. However, the front of the diaper was completely saturated and some moisture did eventually leak out from under the wings. I stopped the test at this point, but had the wicking or channeling been a little more effective it certainly would have absorbed a lot more. I feel this diaper should be good for at least 2~3 wettings without leaking during daily wear and will likely do better if the wettings happen while standing than when seated.

Lying Down

Total Absorbed Volume: 1733 ml (61.1 oz)
Total Wettings: 4
Used to Total Padding Ratio: 89%
Padding to Absorbency Score: 0.87 ml / cm2 (0.20 oz / in2)

Lying Down Rating: 9

The Forsite Under the Sea diaper performed very well when lying down. The first wetting was easily absorbed and distributed quite well through the padding without obvious pooling. Afterward the padding felt swollen but otherwise dry with limited surface dampness. At this point the padding at the front and rear was still mostly dry. During the second wetting there was brief pooling but it was distributed through the mid and lower rear padding quite quickly. I believe the width of the mid padding in this diaper actually helped with moisture distribution a bit as it didn’t form a dam to the degree of the Rearz Select. There was still a bit of dry padding left at the front and much more at the rear after the second wetting and surface dampness wasn’t too apparent. On the third wetting more moisture was distributed to the rear padding and it started to swell with slightly more dampness apparent though there was still some remaining dry padding. Interestingly, the wide padding again allowed for better channeling of moisture toward the rear and the pooling only lasted a short time. There was finally some leakage through the leg gathers on the fourth wetting although there was also significant absorption. At this point, the lower rear padding felt quite saturated and there was a lot of initial pooling, which later subsided. At the end of the test the diaper still felt relatively comfortable and there were still patches of dry padding at the front and rear so I expect had the leak guards held a bit better it may have absorbed a little more. This could be one of the trade-offs of the wide mid-padding, which allowed better channeling of moisture but perhaps resulted in earlier leaks creating a weaker seal on the legs. All in all, I found this diaper particularly well suited to bedwetting and likely to go at least 3 wettings before leakage would be a concern.

2.3 Pattern of Used vs Unused Padding Test Stand/Sit (right) Lying Down (left)

Daily Wear and Bedwetting

The Forsite Under the Sea proved very similar to the Forsite AM/PM during testing for daily and overnight wear. While it had only minor differences from the Trest Elite, Rearz and TotalDry X-Plus diapers, likely owing to similar means of production. I don’t find this construction to be the softest or most comfortable on the market, but the extensive area of padding coverage makes up for the lesser material comfort. Like others of this construction, the biggest issue with this diaper has to do with its mid-padding width, which can bunch up and fold inward or outward between the legs. This will cause an obvious diaper bulge and can somewhat inhibit movement, giving the wearer a bit of a “diaper waddle”. When worn while seated, I found the padding tends to fold inward and the bulge formed when wet can start to direct moisture out of the sides causing it to leak far before it hits its theoretical capacity. This “damming” effect is apparent in many other high absorbency diapers like the NorthShore Megamax and I feel it’s one of the biggest reasons many will never hit their theoretical capacity, but getting proper moisture channels is difficult to get right. During overnight wear, the width of the padding was less of an issue as it tends to stay open and it can actually assist a bit with moisture distribution. I never had any issues with leakage for bedwetting and feel this diaper could be worn without concern even for the heaviest wetters. During daily wear it’s probably not an ideal choice. When seated you may get 2~3 wettings before it leaks and it will likely leak far earlier than expected. If wet while standing you’ll likely get more capacity out of it. That said, it’s a bulky, showy diaper that does little to stay discreet, so even if the capacity works out for daily wear you’re going to have a hard time hiding the fact you’re wearing a diaper. I also found it to be less effective at holding back surface dampness than some of the top performers like the BetterDry. Even so, if you do wear it out and about you’ll find it incredibly durable, with very strong tapes that refuse to loosen or allow sagging. It generally proved resistant to the formation of odors and I never had issues with skin irritation while wearing this diaper. For its price point and style, it’s likely to remain a specialty diaper best suited for infrequent wear at times when you can go an extended time without a change.

Suitability for Bowel Incontinence: 10

The Forsite Under the Sea diaper gets top marks when it comes to suitability for bowel incontinence. This diaper ticks pretty much all the key boxes, with a thick plastic backsheet/dual waistbands to contain odors. It also has extensive rear padding and very tall standing inner leak guards. Moreover, the tapes hold well and the wide padding creates an optimal pouch for bowel containment.

Wear & Tear Tests


The Forsite Under the Sea features a playfully printed plastic backsheet with a thick plastic landing zone and two adhesive tapes per side. The tapes are repositionable and thus can be refastened in any location on the landing zone at any point after the initial fitting so it’s easy to adjust as needed. It features wide dual waistbands to assist in getting a snug fit around the wearer’s waist. It also fits slightly on the larger size, though not as much as the Northshore Megamax, and has an extensive amount of padding coverage.

3.1 Forsite Under the Sea Fastener

Ease-of-Use Rating: 9

The Forsite Under the Sea diaper is quite easy to use and I rank it about the same as the Forsite AM/PM. The tapes hold incredibly well and can be refastened and repositioned multiple times over the landing zone without ever losing their adhesiveness. The waistbands and generous padding coverage make it easy to acquire a snug and secure fit. However, like the Forsite AM/PM the padding in the middle is quite wide and this means it can bunch up a bit, making it feel looser than it might otherwise. Moreover, unlike the AM/PM, this diaper doesn’t feature a wetness indicator and the backsheet patterns don’t fade in any meaningful way when wet so it’s probably not the best choice for a carer environment.

3.2 Forsite Under the Sea Diaper Fit


Comfort Rating (dry): 8

If you like the Forsite AM/PM then you’ll find the Forsite Under the Sea to be nearly identical when it comes to comfort. This diaper features extensive soft padding with waistbands to hold it snugly in place. It has a thick plastic backsheet that’s soft, but not exactly the softest on the market, much like you’d find in the TotalDry X-Plus or Trest Elite Briefs. The thickness could be somewhat of an issue in warm weather, so it’s likely better suited in cooler times. But otherwise, my only real complaint when it comes to comfort is that this diaper runs exceptionally wide, so it’s constantly pushing the wearer’s legs outward and may impede normal walking. That in itself probably makes it better suited for overnight wear, when the width can be all the more helpful.

Comfort Rating (wet): 7

I rank the Forsite Under the Sea about the same as the Forsite AM/PM when it comes to wet comfort. The padding is a bit more absorbent and I noticed slightly less overall dampness. Neither diaper is particularly breathable, due to the thicker plastic/landing zone but the generous padding coverage somewhat mitigates that. Both are susceptible to surface dampness. Otherwise, I had no issues with padding clumping or tearing and the tapes proved incredibly strong. This diaper does tend to swell up when wet, with sagging primarily happening due to the width of the padding rather than any weakness in the structure.

3.3 Forsite Under the Sea Topsheet and Backsheet


Dry Padding Deterioration Proportion: 11.9% (topsheet), 9% (backsheet)
Shake Deterioration Test: 3 shakes to deterioration

Durability Rating (dry): 9
During the dry durability test the Forsite Under the Sea diaper demonstrated a modest amount of padding deterioration. However, the deterioration was largely left to the edges of the padding, which was already very wide and core areas were little affected. For this reason, I give it a slightly higher score than I might otherwise give a diaper based on deterioration measures alone. During testing it proved incredibly resilient, with the tapes holding up to multiple refastenings without any significant loss of adhesiveness. I also didn’t notice any clumping or tearing in the padding, with it largely retaining its original form. I can’t quite say it's the most durable diaper on the market, but certainly near the top. However, it comes with the caveat that this diaper is quite thick and bulky/not ideal for active wearers. Durability again resembles that of the Forsite AM/PM.

Durability Rating (wet): 9

The Forsite Under the Sea diaper is among the top performers when it comes to wet durability, demonstrating very similar performance to the Forsite AM/PM. The tapes hold up incredibly well to multiple refastenings and never showed any sign of coming loose. Likewise, the padding swelled but held in its original condition when wet without any obvious clumping or tearing. It wasn’t a top performer on the wet durability shake test, but I don’t find that to be a useful metric for high absorbency diapers. That said, this diaper is quite bulky and a bit restrictive, which I feel would preclude it from more active wear.

3.4 Forsite Under the Sea Dry Test Deterioration

Discretion Tests


Front Rise Above Waistline (Jeans, Sweatpants): 3 cm (1.2"), 3 cm (1.2")
Back Rise Above Waistline (Jeans, Sweatpants): 7.5 cm (3"), 6.5 cm (2.6")
Side Rise Above Waistline (Jeans, Sweatpants): 5 cm (2"), 5 cm (2")

Profile Discretion Rating: 3

The Forsite Under the Sea diaper does not pay much mind to discretion. This diaper is large and bulk and very easily noticeable, particularly at the rear. Moreover, it rises quite a bit above the waistline and the playful pattern print would be quite obvious were someone to get a glimpse. I think this diaper is well suited for wear around the house, but would not recommend it for going out if your goal is to keep it concealed.

4.1 Forsite Under the Sea Jeans Profile (left) vs Normal Underwear (right)

4.2 Forsite Under the Sea Sweats Profile (left) vs Normal Underwear (right) 


Noise Rating: 5

The Forsite Under the Sea diaper is about the same as the Forsite AM/PM when it comes to noise. Both produce significant noise as a result of the wide construction and thick plastic landing zone. This is particularly evident when standing or sitting and would be tough to hide under all but the thickest dress.

4.3 Forsite Under the Sea Noise Profile

Odor Reduction

Odor Reduction Rating: 8
The Forsite Under the Sea performed about the same as the Forsite AM/PM when it came to resistance to odors. Its biggest downside is the tendency toward surface dampness compared to other premium diapers like the BetterDry. However, it has a very solid build with a plastic backsheet and generous waistbands to lock in any odors and some apparent neutralizing effects in the padding itself.

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