They will be announced on stage at a Samsung Unpacked event at Mobile World Congress and the world will be watching the livestream to get a glimpse of the new designs and see the entire spec list.
However, thanks to multiple leaks, we already have a pretty good idea of what to expect from Samsung come launch day, from its design right down to the features of the new dual-lens camera. This year's Galaxy S flagship doesn't stray too far away from the design of the S8, but it will still be an important update for Samsung nonetheless.
That's why we've put together a chronological round-up of all the major Samsung Galaxy S smartphones from the first to the two expected to launch this week. We've ignored variants - the Neo, Plus, Mini, etc - and stuck to the major phones from each line.
So scan the phones below and see how Samsung has changed its design philosophy as the technology has improved.
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Samsung Galaxy S
First released in June 2010, the Samsung Galaxy S ran on Android 2.1 and had an 800 x 480 Super AMOLED display.
It also had a single-core 1GHz processor and 0.5GB of RAM.
The rear camera was 5-megapixels, while front was just 0.3-megapixels.
Samsung Galaxy S2
Also known as the Samsung Galaxy S II, the refreshed phone was released in April 2011 and sported a similar 800 x 480 screen as its predecessor.
The processor got a bump up to dual-core and 1.2GHz, and there was 0.75GB of RAM.
The rear camera was 8-megapixels this time, with a 2-megapixel front-facing cam.
Samsung Galaxy S3
Again sticking with the Roman numerals, so therefore technically known as the Samsung Galaxy S III, this model came out in May 2012 and was the first in the series to have a HD screen.
Its resolution of 1280 x 720 was pretty revolutionary at the time. It also sported Android 4.0 Ice Cream Sandwich.
There was a 1.4GHz quad-core processor with 1GB of RAM on launch, although Samsung stuck with an 8-megapixel rear camera.
Samsung Galaxy S4
Released in April 2013 and ditching the Roman numerals that nobody used when referring to Galaxy phones on the internet anyway, the S4 had a 5-inch Full HD display.
It also upped the processing power to a 1.9GHz quad-core chip, with 2GB of RAM.
The rear camera had a jump too, up to 13-megapixels.
Samsung Galaxy S5
Coming in April 2014, the S5 also had a Full HD screen but it was slightly bigger, measuring 5.1-inches (an LTE-A model eventually upped that to 2560 x 1440).
There was a 2.5GHz quad-core processor on board, with 2GB of RAM. And the rear camera was once again improved, to a 16-megapixel module.
Samsung Galaxy S6
April 2015's Galaxy S line was the first to offer two separate devices at the same time.
The more standard Galaxy S6 featured a flat 2560 x 1440 Quad HD Super AMOLED display, measuring 5.1-inches.
It ran on a Samsung-made octa-core processor, had 3GB of RAM and a 16-megapixel rear camera capable of recording Ultra HD footage. A 5-megapixel camera was adopted for the front.
Samsung Galaxy S6 edge
Like its stablemate also released in April 2015, the Galaxy S6 edge had a 5.1-inch Quad HD screen, octa-core processor, 3GB of RAM, 16-megapixel rear camera and 5-megapixel front-facing cam.
Where it differed is that the sides of the display are curved and wrap around to give the illusion of no bezel - a radical alternative at the time.
Samsung Galaxy S7
The Galaxy S7 was announced in February 2016 and came with a 5.1-inch QHD display (2560 x 1440).
Like the S6 before it, it was the flat-screen version of two handsets, but added a dual-pixel 12-megapixel camera for better low light photography and faster octa-core processor.
Samsung Pay was enabled on the phone, which could work through NFC and magnetic strip systems.
Samsung Galaxy S7 edge
The Galaxy S7 edge was (and even now it's two years old, still is) a true flagship phone in every respect. It too was announced in February 2016 and its 5.5-inch dual edge QHD display was simply superb.
All of the same features as the S7 were on board and the design was a touch rounder than the S6 edge that preceded it.
Samsung Galaxy S8
The Samsung Galaxy S8 was the first to introduce the Infinity Display, that referred to the fact it had an edge-to-edge display with virtually no bezels. The front-mounted home button was moved to the back too, albeit in a slightly awkward position - something Samsung should correct with the S9.
While there was also a second variant in the Plus, the standard Galaxy S8 came with curved edges as standards.
Samsung Galaxy S8+
The Samsung Galaxy S8+ is exactly the same as its smaller S8 sibling in almost every respect, save from a larger, 6.2-inch display and a 3,500mAh battery compared to a 3,000mAh cell on the S8. While a 6.2-inch screen may sound huge, thanks to the Infinity Display design, the S8 Plus wasn't much bigger than an iPhone 7 Plus.
The extra screen real estate made it an absolute joy to watch movies on and the battery kept it going for hours on end. We loved the S8+ so much we considered to the one of the, if not the best Android phone of 2017.
Samsung Galaxy S9
On the surface the S9 looks very similar to the S8 from 2017. The phone still offers that curved edge design and comes with a 5.8-inch OLED screen size and will be, once again, waterproof.
The Galaxy S9 will offer AR emoji, where the phone will create a 3D avatar by scanning your face and create a range of custom emoji for you. These can be used when chatting in WhatsApp or Facebook Messenger, for example, rather than using basic emoji. Social.
Samsung Galaxy S9+
Externally, the new Galaxy S9+ looks like the 2017 S8+, but this year there's more than just a size difference between these two handsets, with the larger Galaxy S9+ model getting an secondary camera for 2x optical zoom.
The camera is the main focus point for the Galaxy S9 models, with both handsets offering a new dual aperture main camera. This integrates a mechanical aperture, giving you f/1.5 for low light and f/2.4 for brighter conditions.