Patek Philippe Aquanaut Travel Time Advanced Research 40.8mm 18K White Gold Blue Dial Fixed Bezel (Ref# 5650G-001)

Patek Aquanaut Travel Time Advanced Research 5650G: The Terminator

Today we have one of the most important modern Aquanauts, the Patek Philippe Aquanaut Travel Time Advanced Research, reference 5650G-001, nicknamed the Terminator by some collectors. Released in 2017 and limited to only 500 pieces, many treat it as the unofficial 20th anniversary Aquanaut. It is one of the rarest Aquanauts Patek has made and still one of the most talked about today. What makes it special is not just the dial color, it is a semi-open dial that actually shows the travel time mechanism working as you use it.

Watch the full unboxing

The 5650G head-on, blue embossed Aquanaut dial fading darker toward the edges

Patek Philippe Aquanaut Travel Time Advanced Research 40.8mm 18K White Gold Blue Dial Fixed Bezel (Ref# 5650G-001) - Price on Request

Case, Size, and Wearability

The case is 40.8mm in diameter, made in 18-karat white gold with a brushed bezel, sapphire crystals front and back, and 120 meters of water resistance. Patek lists the thickness at 11mm with a lug-to-lug of 47.3mm. Our measurements come in around 10.6mm thick and right about 47mm lug-to-lug, kept here for reference only. The watch weighs 145 grams, roughly a third of a pound. It is not too light and not too heavy, and the thin, compact case gives it excellent wearability for daily use.

Case profile showing the brushed white gold bezel and slim case

On the scale at 145.8 grams, roughly a third of a pound

The Fume Dial and Open Aperture

The dial is instantly recognizable. You get the blue embossed Aquanaut pattern, but with a fume fade that darkens toward the edges, giving it more depth and a slightly more serious feel than a standard blue Aquanaut. Then there is the semi-open section between 8 and 10 o'clock. Patek does not experiment with openworking often, so seeing it here on an Aquanaut is unusual. That opening is not decoration. It reveals part of the travel time actuator that controls the local hour hand.

Macro of the fume dial and the semi-open section between 8 and 10 o'clock

How the Travel Time System Works

The pushers on the left side of the case move the local hour forward or backward in one-hour increments, and you can watch the mechanism move through the dial as you adjust. When you land in a new time zone, you set the local hour on the fly without stopping the watch or affecting the minutes. There is also a hidden, skeletonized home time hand: when you track a second zone it is visible, and when local and home time match it tucks under the main hour hand to keep the dial clean. You also get day and night indicators for both local and home time, plus a radial pointer date at 6 o'clock.

Through the aperture, the travel time actuator that drives the local hour hand

The dial's local and home time indications with day and night read-outs

Caliber 324 S FUS

Inside is the Patek Philippe caliber 324 S FUS, a self-winding travel time movement with roughly a 45-hour power reserve. The Advanced Research designation reflects Patek's experimental engineering program, and here the payoff is a travel time actuator you can actually see operate rather than one hidden entirely under the dial. It gives the watch a more mechanical, honest feeling in daily use.

The self-winding caliber 324 S FUS and gold rotor through the sapphire caseback

Strap, Clasp, and Rarity

The watch comes on a blue composite rubber strap matched to the dial, fitted with an 18-karat white gold double fold-over deployant clasp. The strap is a core part of the Aquanaut identity and keeps the piece feeling sporty and casual despite the white gold and the complication. Almost ten years on, very few Aquanauts have captured collector attention the way this one has. You have a complicated travel time watch, an Advanced Research movement, a semi-open dial that shows the system working, and the casual appeal of the Aquanaut, all in one reference. If you would like to see it or talk it through, reach out to us at Watches Off 5th.

The 18K white gold double fold-over deployant clasp on the blue composite strap

On the wrist, sporty and compact despite the white gold and complication

The 5650G presented on its Patek Philippe box