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PFAS in Waterproof Smartwatches & Fitness Trackers: Which Brands Grade Best and Worst

Swatch-brand waterproof watches consistently earn B-grade ratings in our PFAS assessment model, based on materials transparency and manufacturing disclosure. The Swatch SWATCH PACIFIC SEA NETTLE and five other models in the Swatch line show lower concern for PFAS contamination when evaluated against available public data. Conversely, TomTom fitness GPS watches and Withings hybrid smartwatches receive F-grade ratings, indicating higher concern due to limited material disclosure and typical fluoropolymer use in waterproofing.

This guide examines the PFAS profile of leading waterproof smartwatches and fitness trackers on the market today. We analyze 15 models across three brands, separating manufacturer claims from third-party verified data, and explain why waterproof electronics present particular PFAS risks. Our model-based safety estimates are derived from material sourcing, published transparency reports, and known industry practices, not laboratory testing of individual units.

Quick Comparison Table

Product	Brand	PFAS Grade	Safety Score (out of 100)	Verdict
Swatch PACIFIC SEA NETTLE	Swatch	B	85	Lower concern
Swatch Chrono 42 Quartz	Swatch	B	85	Lower concern
Swatch Neon Seppia Big Bold Chrono	Swatch	B	85	Lower concern
Swatch MEDUSAE Quartz	Swatch	B	85	Lower concern
Omega X Swatch Mission To Moon	Swatch	B	85	Lower concern
Swatch SEA WASP	Swatch	B	85	Lower concern
TomTom Golfer 2 GPS Watch	TomTom	F	40	Higher concern
TomTom Spark Music GPS Fitness	TomTom	F	40	Higher concern
TomTom Multi-Sport GPS Watch	TomTom	F	40	Higher concern
Withings ScanWatch Vitals	Withings	F	40	Higher concern
Withings ScanWatch HWA09 Hybrid	Withings	F	40	Higher concern
Swatch Scubaqua Sea Nettle	Swatch	F	40	Higher concern
TomTom Runner GPS Watch	TomTom	F	40	Higher concern
TomTom Spark GPS Fitness Watch	TomTom	F	40	Higher concern

Why PFAS in Waterproof Watches Matter

Per- and polyfluoroalkyl substances, or PFAS, are "forever chemicals" used in waterproofing, stain resistance, and non-stick coatings. When present in wearable electronics that touch skin for extended periods, PFAS can leach into sweat and eventually accumulate in human tissue. Smartwatches and fitness trackers are worn continuously, often in contact with skin barrier areas, increasing potential exposure compared to occasional-use items.

Most waterproof watches rely on fluoropolymer gaskets, seals, and membrane coatings to achieve water resistance. These materials frequently contain PFAS compounds. Our safety grades reflect the likelihood that a given product uses such chemistries, based on brand transparency, material sourcing statements, and industry standards for that product category.

The Swatch Advantage: B-Grade Leaders

Six Swatch models earn B-grade safety scores of 85 out of 100, our model-based estimate from materials and public disclosure, not a lab test. These include the SWATCH PACIFIC SEA NETTLE, Chrono 42 Quartz, and Omega X Mission To Moon collaboration. Swatch's published commitment to phasing out PFAS-containing materials in its manufacturing supply chain, combined with its emphasis on recyclable watch casings and band materials, suggests a lower concern profile compared to competitors.

Swatch PACIFIC SEA NETTLE: Materials and Brand Claims

This model features a plastic case and silicone strap, both standard materials that do not inherently require fluoropolymer waterproofing. Swatch states commitment to sustainable sourcing practices, though the brand does not publicly claim PFAS-free manufacturing on this specific SKU. The B-grade reflects moderate material transparency and known design practices, not a third-party lab verification of PFAS absence.

Pros: Lightweight, affordable, synthetic materials reduce risk of fluorinated surface treatments. Swatch's supply chain initiatives suggest manufacturer intent to reduce PFAS reliance.

Cons: No third-party PFAS testing published for this model. Plastic components may still contain trace fluoropolymers in adhesives or protective coatings. Warranty and repair practices not detailed.

Swatch Chrono 42 and Neon Seppia Big Bold Models: Consistent B Performance

Both Chrono 42 and Neon Seppia variants maintain the same material philosophy: plastic cases, quartz movements, and synthetic elastomer straps. They earn B-grades through the same transparency and supply-chain reasoning as the PACIFIC SEA NETTLE.

Pros: Consistent design approach across multiple SKUs suggests standardized, lower-risk manufacturing. Quartz mechanisms reduce electronics-related contamination risk.

Cons: Swatch has not published detailed PFAS avoidance protocols per product line. No independent certification or lab results on file.

Swatch SEA WASP and MEDUSAE: Specialized Designs, Same Concerns

The SEA WASP and MEDUSAE models also receive B-grades despite their specialized aesthetic and technical positioning. Both use standard Swatch plastic and silicone construction, maintaining the lower-concern profile established by the brand's material commitment.

Pros: Visual and feature differentiation does not increase material complexity or PFAS reliance. Accessible pricing supports widespread adoption of lower-concern watches.

Cons: Specialized branding may obscure identical material composition and equivalent risk levels to baseline Swatch models.

The F-Grade Risk Zone: TomTom and Withings Fitness Trackers

TomTom GPS fitness watches and Withings hybrid smartwatches receive F-grade ratings of 40 out of 100, our model-based estimate from materials and public disclosure, not a lab test. These products feature integrated electronics, advanced sensors, and complex waterproofing systems that typically rely on PFAS-containing fluoropolymers. Neither brand publicly discloses PFAS reduction strategies or third-party material verification.

TomTom Golfer 2, Spark Music, and Multi-Sport: GPS Complexity = Higher Concern

The TomTom Golfer 2, Spark Music, and Multi-Sport models integrate GPS chipsets, touchscreen displays, battery systems, and data transmission circuits. These electronics require advanced conformal coatings, sealants, and gaskets. TomTom does not publish material composition or PFAS avoidance commitments in available sourcing documents.

Pros: Feature-rich fitness tracking and GPS accuracy for outdoor activities. Water resistance rated to depths suitable for swimming and water sports.

Cons: No material transparency regarding fluoropolymer use in seals, gaskets, or electronic coatings. Complex internal architecture increases surface area for potential PFAS accumulation. No brand commitment to PFAS phase-out identified in public disclosures.

TomTom Runner and Spark GPS: Standard Fitness Watch Profile

The Runner GPS and Spark GPS Fitness watches follow identical material and construction patterns to the higher-spec models, yet still receive F-grades due to lack of published PFAS mitigation strategy. GPS and fitness sensor integration necessitates waterproofing chemicals that remain undisclosed.

Pros: Established GPS and fitness tracking reliability. Proven durability in athletic contexts.

Cons: Standard TomTom policy of minimal material disclosure extends to PFAS concerns. No differentiation from higher-risk product lines.

Withings ScanWatch Vitals and HWA09 Hybrid: Smartwatch Complexity

The Withings ScanWatch Vitals and HWA09 Hybrid models combine analog watch styling with digital health sensors, creating hybrid architectures that demand advanced waterproofing. Withings does not publicly commit to PFAS avoidance or provide material composition transparency for waterproofing systems. The F-grade reflects this absence of disclosure and the high likelihood of fluoropolymer-based water sealing in hybrid smartwatch designs.

Pros: Hybrid analog/digital design appeals to users who prefer traditional watch aesthetics. Health monitoring features (ECG, pulse, activity tracking) are well-established.

Cons: Sensor integration and hybrid mechanics require sophisticated sealing systems. No published PFAS reduction policy. Material composition of gaskets and conformal coatings not disclosed.

The Swatch Outlier: Scubaqua Sea Nettle F-Grade

Notably, one Swatch model, the Scubaqua Sea Nettle, receives an F-grade despite the Swatch brand's otherwise strong B-grade performance. This watch is designed for professional diving and features advanced water resistance (rated to greater depths than standard Swatch models). The specialized engineering, additional sealing layers, and enhanced gasket systems required for extreme waterproofing increase reliance on fluoropolymer compounds. While Swatch's corporate commitment to PFAS reduction is noted, this particular model's diving-specific design necessitates material choices that raise PFAS concern.

Pros: Professional-grade water resistance certified for diving applications. Swatch brand heritage and durability reputation.

Cons: Specialized diving engineering contradicts standard Swatch material philosophy. F-grade reflects higher PFAS concern due to advanced waterproofing requirements. Not a practical choice for users seeking lower PFAS exposure.

What to Avoid

Avoid smartwatches and fitness trackers from manufacturers that do not publish material composition or supply chain practices related to waterproofing chemicals. F-grade products from TomTom and Withings represent this category. Specifically, avoid:

• Products with GPS, touchscreen displays, or integrated electronics without published waterproofing material specifications
• Watches marketed as "extreme waterproof" or rated for diving without third-party verification of PFAS avoidance
• Brands that do not include PFAS reduction in corporate sustainability reports
• Models where repair, replacement, or refurbishment policies are unclear, as secondary exposure to PFAS sealants may occur during service

Additionally, consider expanding your search to waterproof gear categories that may present cumulative PFAS exposure if you wear multiple waterproof products daily. Watches worn continuously pose continuous skin contact; combined with rain jackets and other treated clothing, total PFAS load may increase.

Our Pick: Why Swatch B-Grade Models Represent Lower Concern

The Swatch PACIFIC SEA NETTLE and its five B-grade siblings emerge as the lower-concern choice for waterproof smartwatch use, based on available materials and data. These watches share a consistent material philosophy: plastic cases, silicone or elastomer straps, and quartz mechanisms that do not require advanced fluoropolymer sealing systems. Swatch's published commitment to phasing out PFAS-containing materials in manufacturing, while not verified through independent lab testing, distinguishes the brand from competitors like TomTom and Withings that offer no such disclosure.

The B-grade (85/100) is our model-based estimate from materials and public disclosure, not a lab test result. It reflects lower concern relative to F-grade alternatives, meaning association with documented PFAS use is reduced based on known material practices and brand transparency. No product is proven "PFAS-free" without third-party lab verification; these grades indicate relative risk within the smartwatch category.