Info provided by Wouter Huitzing (prior to his 2019 FKT run):
The Pieterpad is the most famous and longest* hiking trail in The Netherlands, spanning an official distance of 498 km. It starts in the north in Pieterburen, and goes to the south (St. Pietersberg), where a continuation on the European trail GR5 is possible. Of course the reversed direction is possible too. The trail is mostly hiked by older people, walking one or two days during the weekend, but a few fast attempts have been made.
The fastest time I could find is set by Lucja Leonard and Marina Ranger, starting 27th July and finishing in 5 days (exact time unknown). Their progress was documention on the Facebook-page Simply Runderful and both wrote detailed blog posts afterwards (Marina, Lucja). This was fully supported. [Faster times are listed below.]
The official Pieterpad website has a news item (Dutch) stating Edwin van Nieff completed the trail in six days (16th - 21st May 2004). This probably makes him the fastest male, but I have no idea if this is supported or not, not much details can be found about this performance.
The trail also had a number of stage race attempts, called the PieterROGPad (Dutch), having the finishers in 7 days. Fastest net time was set by Karl Graff in 2000: 55 hours and 3 minutes. Fastest female was Ria Buiten in 2001: 60 hours and 23 minutes. Of course the net time is not really a reliable metric for things like this, it would be faster to just run 1 km a day for two years.
Not many other attempts are documented. There is not much of a FKT or thru-hike spirit in The Netherlands, so I don't think many attempts have been made.
* The Kustpad (Coastal Path) is longer, with a total of 721 km, but this one has been split into 5 parts, I can't find any official documentation if this is 1 trail or as 5 trails.
Addition to the story above:
The blog of the support driver of Marina and Lucja mentions a start time of 6:00 on day 1 and a finish on day 5 where he drove up the st.Pietersberg at lunchtime and the ladies arrived half an hour after he parked the car. That would mean they did the course in about 4 days and 7 or 8 hours.
Somehow I really want to get to the bottom of this. Let's try to recreate the events of the last day. We have the following information:
- The day started near Swalmen, this post mentions another 85 km remaining, this post mentions Swalmen.
- The location of this picture is bit above Roermond, the long sleeves imply it's early morning, and it's light outside. Sunrise was around 05:52 that day. It is likely that they started around 06:00 every day (since it was not really meant as a FKT, more as a stage race). Ultraned also mentions the 06:00 start (we'll get back to that page)
- The next relevant post mentions breakfast in Echt. which is around 22 km on that stage (meaning 63 km remaining). "Breakfast" is the only reference to time here, and that's not exactly concrete.
- There is a mention of Windraak in the support driver's blog. From there, it's another 30 km to go. The blog does mention lunch in Windraak, but once again without a specific time. A short addition: the timeline described in this blog is lunch in Windraak, then driving to St. Pieterberg, which is at least a 35 minute drive (probably slower due to the caravan).
- They had to do a detour in Maastricht due to the Triathlon being held that day. There is a picture of them crossing the run, but once again no concrete timestamps here.
- The finish photo shows a route marker that is almost North/South directed. The shadow indicates that the sun is close to the West, but not yet.
So we have very little concrete information here. The "7 or 8 hours" sounds too fast to me, 8 hours is just too fast for a day of 85 km, based on the running speed shown in the few videos of the last day. The 18:00 finish that Ultraned guesses should mean a 12 hour day, but that doesn't match the shadow on the finish foto, it would be in the southeast quadrant, not the northeast. So I'm just going to meet in the middle and guess 4 days 10 hours.