While I do not know about it being anywhere closest to the most thin I really love this model from Junghans. 7.3mm is not bad though.

 

That is exactly the one that I have my sights on, but with the white dial! Its almost perfect!

Hamilton JazzMaster Auto Thinline

Baroncelli Heritage Gent I’ve actually tried this one in person…it is a feather

Longines Presence @ 8.3 with an excellent movement.

Many thanks. I will look into all of these!

Used market Ludwig (6.8) and Tetra (6.5) with the alpha. Or settle for a 5mm Stiletto Eco Drive.

I'm guessing you're not in the market for Jaeger-LeCoultre's dirt cheap world famous 5mm thick mechanical watches. I got one for around 300 USD, though the other one was just above your budget.

I had not even considered JLC at my budget! I would certainly consider JLC and go over budget for one! Thanks.

 

Hamilton JazzMaster Auto Thinline

 

Baroncelli Heritage Gent I’ve actually tried this one in person…it is a feather

 

Watches with the ETA manual wind and 2892 auto are some of the thinnest current ones being sold.

 

Longines Presence @ 8.3 with an excellent movement.

 

Still one of my favs. I believe it’s 9.4mm when I measured it. It’s been awhile but wears perfect

 

Used market Ludwig (6.8) and Tetra (6.5) with the alpha. Or settle for a 5mm Stiletto Eco Drive.

I'm guessing you're not in the market for Jaeger-LeCoultre's dirt cheap world famous 5mm thick mechanical watches. I got one for around 300 USD, though the other one was just above your budget.

 

This Mont-Blanc 112515 (cosc!) is 5.8mm - I’ve always admired it from afar:

Montblanc Heritage Chronométrie Watch 112515

From the expert watchmakers of Montblanc, this luxury watch for Gents is carefully constructed with a sleek and beautiful build. Montblanc crafted this watch for those always on the go, but still want to stay fashionable. Its Silver dial houses exquisite markings that help you keep time. The...

www.miamilakesj.com

 

The now discontinued CWard 595 is 5.95mm thick, and can be had used for next to nothing

Hands-On with the Christopher Ward C5 Malvern 595 - Worn & Wound

The rules around exactly what makes a dress watch seem to vary depending on who you ask, but based on most interpretations the C5 Malvern 595 would certainly qualify. Modestly sized, clean, time only, and only 5.95 millimeters thick, the C5 Malvern 595 is delightfully thin for a mechanical...

wornandwound.com

 

Thinnest 39mm mechanical screwdown crown with WR.
9.9mm.
~1k€

And oh so comfortable. 😌

Models without manufactory movement

DAMASKO is a German watch manufactory specialising in high quality mechanical watches and chronographs.

www.damasko-watches.com

 

Anything from Nomos perhaps?

 

Nomos (and Stowa) gets into objective-vs-subjective thickness—the even if they’re technically thinner that some of the other watches here (off the top of my head I can’t recall) the cylindrical case will make them seem taller.

 

I'll second the Concord. One of the coolest thin divers, they also do it in a dress version. Bulgari did something similar too.

 

Epos Originale 3408... 5.9mm, ~$1500:

 

Mido Baroncelli Heritage

Automatic, 3 hands + date, 7.3mm, $1040

 

Arrived yesterday and I am very happy with it!