Seiko Alpinist SPB121 Review & Guide

Seiko Alpinist SPB121 Review & Guide

Photo: Carat & Co

Seiko Alpinist SPB121 Review & Guide

In 1961 Seiko first introduced their first serious professional sports watch meant to be worn by Japanese mountain climbers. The inspiration for this watch came from ”Yama-Otoko”, which means mountain men in Japanese, and this is the original purpose that this watch was made for. As Japan mostly is covered by Mountains the men who worked and spent their free time there really needed a reliable watch that could handle the rugged terrain without having to worry too much about accuracy.

The alpinist has since its release in 1961 been in production from time to time, but ever since the fourth generation of the Alpinist was released in 2003 the demand for these watches has increased significantly. In January 2020 Seiko once again released three new Alpinists for the market, one which perhaps is the most desirable, the Seiko Alpinist SPB121. This watch features an automatic movement, 39,5mm, stainless steel, and a green dial with gold markers and hands. Let’s take a deeper look at this watch and understand why this watch is a must-have and is so desirable by watch enthusiasts worldwide!

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The Dial is sunburst green with applied golden numeral indexes and lume dots with Seikos own LumiBrite. An applied Seiko logo is positioned in the center at 12 o’clock. Three lines of text and the Prospex logo can be found printed with white lettering at the bottom center of the dial. The Prospex logo not only makes a tough statement, that this would be a professional watch from Seiko, but is also new for the Alpinist series. The SPB121 is equipped with an inner rotatable compass ring which can be turned using the crown positioned at the 4 o’clock position.


The hands are golden with the classical Alpinist minute, hour, and seconds hand. LumiBrite is richly applied to the hands and because of this, it is really easy to tell the time in the dark. The white LumiBrite hands are a great contrast from the green sunburst dial which makes it easy to tell the time.


The case is in stainless steel and measures 39.5MM and really is a great size for all wrists. The lug-to-lug size is 46.4MM, and with the original leather strap that comes with the watch, it both be used both as a dress watch and also a professional tool watch. The case does require the user to remove the spring bars from the inside, which might take some practice but is a rather simple task.

Once you get this going it is really simple to change the strap of the watch to a more fitting strap depending on what you are about to attend. For a more formal dinner, the original leather strap is a good alternative, while a nato strap might give you a more relaxed or sporty look. It is water-resistant to 200M meaning that you are able to swim and dive with your watch without having to worry about the watch not being able to handle the static pressure.

It is a screw case back with an open window making it possible to view the movement inside. The new SPB121 is upgraded with a sapphire Chrystal which is AR-coated on the inside which prevents the AR to fall off after some time of usage, it is also the first Alpinist with a date magnifier which makes it easier to tell which date it is.

Seiko Alpinist SPB121 Review & Guide


Photo: Watchonista


The bracelet that comes with the Seiko Alpinist SPB121 is a calfskin band with a pressed print making it look like some type of reptile. Attach is a three-folded clasp with a push-button release in stainless steel. The folding clasp makes it possible to adjust the length of the bracelet by adjusting which hole the pin is positioned in.

This is similar to an ordinary and more common pin buckle but of course, gives a more luxurious and robust feeling. The black version of the Seiko Alpinist reference SPB117 does come with a stainless steel bracelet, and if you prefer this could be bought as an extra option to your SPB121, with that said it is possible to have the watch equipped with an OEM stainless steel strap from Seiko.


The movement of the new Seiko Alpinist SPB121 is upgraded from the previous 6R15 to the new Seiko in-house caliber 6R35. Not only is this a more delicate and small changed movement, but the power reserve is increased to 70 hours.

The movement is capable of telling hours, minutes, seconds and the date, it is automatic but also features a hacking function and winding function. The movement’s frequency is 21.600VpH and has 24 jewels with a recommended accuracy of +25 to -15 seconds per 24 hours.


The new Seiko Alpinist with the green dial really reminds of the legacy and history of the model. It is updated and with this model that unexpectedly was released it really feels like Seiko themselves have listened to what the market demanded from them. The new Alpinist has received small visual improvements that are great updates such as the date magnifier and the Prospex logo.

However, not to miss out is the great updated 6R35 movement with an impressive updated power reserve of 70 hours. It is easy to understand why this model has become so popular and reached such high demand.

The similar Seiko Alpinist SARB017 is available to order on Amazon


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