Yes, the vast majority of Dutch trains operated by NS (Nederlandse Spoorwegen) are equipped with toilets, but there is one notable exception to keep in mind. All Intercity (IC) trains, which connect major hubs like Amsterdam, Rotterdam, and Utrecht, are equipped with modern, accessible restrooms. However, the older models of the Sprinter (SLT) trains—which serve as local/regional "all-stations" stoppers—historically did not have toilets because they were designed for short-distance commutes. In response to public demand, the NS began a massive retrofitting project, and by 2026, almost all Sprinter trains have been either replaced or updated with toilets. These onboard restrooms are generally free of charge and are vacuum-flush systems. If you are on a train without a toilet, you can usually find "Pay-to-Use" facilities (Sanifair) at nearly every station in the Netherlands. For travelers on international high-speed lines like the Eurostar or ICE that pass through the Netherlands, toilets are standard and high-quality. You can check the "NS app" for your specific train's facilities, as it displays icons for Wi-Fi, bicycle storage, and toilets for each scheduled service.