The Samsung Galaxy S9 and S9+ are Android-based smartphones unveiled, manufactured, released and marketed by Samsung Electronics as part of the Samsung Galaxy S series. The devices were revealed at the Mobile World Congress in Barcelona on 25 February 2018, as the successors to the Samsung Galaxy S8 and S8+.^[6]

The Galaxy S9 and S9+ have nearly identical features to the S8 models, with the same display sizes and aspect ratio as their predecessors. One highly regarded change to distinguish between the models is the location of the fingerprint sensor. While the S8's is found beside the camera, the S9's is directly underneath it. Most notably, however, the S9 line is equipped with several camera improvements over the S8.

The phone received generally favorable reviews, with critics mostly noting the enhanced camera and better positioned fingerprint scanner. Critics, however, still criticize the phone being too similar to its predecessor. It is available in seven colours (Lilac Purple, Midnight Black, Titanium Gray, Coral Blue, Sunrise Gold, Burgundy Red, and Polaris Blue). It was succeeded by the Samsung Galaxy S10 in March 2019.

Many Galaxy S9 features and design changes were leaked weeks before the official launch,^[7] and the official launch video was leaked a few hours prior to the unveiling.^[8]

In mid-2018, Samsung published a series of mockery commercials named "Ingenius" against iPhones' lack of the Galaxy S9's functionality, including an audio connector, memory card expandable storage, as well as allegedly inferior network transfer rates and camera performance.

In one of those commercials, an unhappy customer failed to locate a memory card slot on her iPhone, to which the Apple Store employee told her that the device lacks such, and suggested her in one word to rely on cloud storage as storage expansion instead, even though it depends on Internet access to function and has slow transfer rates and high latency compared to memory cards. The customer stated that she did not "want her stuff up there", but locally, to which the Apple store employee suggested purchasing a model with more internal storage.^[31]

John McCann from TechRadar complimented the improved camera and the new location of the fingerprint sensor, but criticized that it was too similar to its predecessor (Galaxy S8) and had limited AR Emoji functionality.^[32]

Brian Heater of TechCrunch reviewed the S9+ on 8 March 2018, and said that the phone is built on the "success [of the S8] in a number of ways".^[33]

Computerworld gave the phone a positive review and said it was "measurably better than its predecessor", but did note there wasn't a new feature that was particularly "exciting".^[34] PC Magazine also gave the Galaxy S9 and S9+ positive reviews.^[35]

CNBC's Todd Haselton said on 8 March that the S9+ was superior to the S9, for reasons such as the larger screen and second camera, as well as more RAM and battery power.^[36]

Samuel Gibbs from The Guardian gave the S9+ 5/5 stars, with the headline it was "the best big-screen smartphone by miles". Screen and camera were praised, but the review noted battery life could be better. He also appreciated the inclusion of a headphone jack, despite many other phones not having one.^[37]

The larger S9+'s camera received a score of 99 from DxOMark, which, at the time was the highest score awarded by them to a mobile device camera.^[38] It was soon surpassed by the Huawei P20 and P20 Pro, which scored 102 and 109 respectively.^[39]

Dan Seifert of The Verge gave the S9 a score of 8.5, stating that its performance, camera and design were satisfactory. However, he was not amused by the average battery life and the addition of Bixby, also saying that Samsung has a poor history of updating their smartphones.^[40]

Ryan Whitwam from Forbes noted that, in 2018, the 6 GB RAM of the S9+, compared to the 4 GB of the S9, is "unlikely [to] [...] make any difference in daily usage" because "Android doesn’t benefit from 6 GB of RAM right now. Maybe in the future, but not now."^[17]

• Samsung Galaxy
• Samsung Galaxy S series