Zharkova started swimming at the age of seven, when her parents introduced her to swimming. Within six months, she was accepted for the school of Olympic Reserve of Ukraine where she spent a total of 10 years.^[2]

Zharkova represented Ukraine in various European swimming championships while attending the school of Olympic Reserve of Ukraine.^{[citation needed]}

In 2008, Zharkova was introduced to freediving and began active training.

In 2009, she participated in a world championship held at Aarhus, Denmark. Zharkova set new Ukraine's national records in freediving.

In 2010, Zharkova competed in Ukraine, Russia and Latvia. Each participation brought Zharkova a new Ukraine's national record.

In 2011, the first depth competitions AIDA International World Championship were held at Kalamata, Greece. Zharkova's first participation in the depth competitions put her near the top freedivers in the discipline, taking 6th place in the CNF discipline (constant weight, no fins). She also set new Ukraine national records in the discipline. (AIDA WC-2011 – FIM – Nataliia Zharkova on YouTube)

In 2012, Ukraine first participated in the team world championship event, held in Nice, France. Zharkova represented Ukraine along with Alexander Bubenchikov and Valentin Kuznetsov. Zharkova improved her previous national records and took 5th place in the world rating.

In 2013, the AIDA International World Championships were held in Kalamata, Greece. Zharkova along with Natalia Molchanova won medals in all of the disciplines of the championship.

• Silver – CNF (Constant weight apnea without fins), 60 m
• Silver – FIM (Free immersion apnea), 78 m
• Bronze – CWT (Constant weight apnea, Bi-fins), 85 m

In 2013–2015, Zharkova was a finalist in the Pool World Championship held in Belgrad, Serbia.

In 2015, the AIDA International Depth World Championship was held in Limassol, Cyprus. Zharkova's results were

• Bronze – FIM (Free immersion apnea)
• Bronze – CWT (Constant weight apnea, with a monofin)

In 2017, Zharkova won two gold and one bronze medal at the Championship of Europe held in Kaş, Turkey. She set two new world records according to CMAS.^[3] All dives of that championship were filmed with the Dive Eye underwater drone.

• CWT BF (Constant weight apnea, Bi-fins) – 85 m in 2 min 51 sec – gold, world record^[4]
• CNF (Constant weight apnea without fins) – 65 m in 2 min 41 sec – gold, world record^[5]
• Constant weight apnea CWT – 85 m in 2 min 36 sec – bronze.

In 2018, Zharkova won two gold medals at the CMAS 3rd Free Diving World Championship held in Kaş, Turkey. She again set two new world records:

• CWT BF – 89 m in 3 min 5 sec – gold, world record;
• CNF – 70 m in 3 min 5 sec – gold, world record.^[6]

In 2019, she won gold in CWT, and sat an AIDA national record at the Caribbean Cup 2019 competition in Roatan, Honduras with a 100 m dive.^[7][8]

A few days later, she won gold, two silver, and bronze medals at CMAS 4th Freediving Outdoor World Championship at Roatan, Honduras, and set one world and two national records:

• CNF – 67 m in 3 min – silver;
• CWT – 102 m in 3 min 20 sec – bronze, national record;
• CWTB – 93 m in 3 min 20 sec – gold, world record;
• FIM – 90 m in 3 min 25 sec – silver, national record.^[9]

Also in 2019, Zharkova took gold in CNF with 66 m at the AIDA Depth World Freediving Championship in Nice, France.^[10]

In 2021, Zharkova won gold, silver, and bronze medals at the 5th CMAS Freediving Outdoor World Championship held in Kaş, Turkey, and set two national records:

• FIM – 91 m – gold, national record;
• CNF – 67 m – silver;
• CWTBF – 97 m – bronze, national record.^[11]

At 2021 AIDA Freediving World CUP in Sharm El Sheikh, Egypt, Zharkova took three gold (in CWT, CNF and CWTB) and one silver (FIM) medals.^[12]

Currently Zharkova is a master Instructor at AIDA International, instructor (Emergency First Response-EFR). She is a chairman of the Freediving committee at UFUA (Ukrainian Federation of Underwater Activities) and is a member of the CMAS international committee. She is an author of multiple training programs and a coach at the Deep Division freediving school in Kharkiv, Ukraine. Zharkova conducts training in warm climate locations, most notably in Dahab, Egypt and actively prepares for upcoming competitions.

• DYN, Dynamic apnea with fins – 172 meters
• DNF, Dynamic apnea without fins – 132 meters
• FIM, Free immersion apnea – 91 meters
• CWT, Constant weight apnea – 102 meters
• STA, Static Apnea – 6 minutes 02 seconds^[13]
• CWTBF, Constant weight apnea, Bi-fins – 97 meters, national record
• CNF, Constant weight apnea without fins – 70 meters.

During her career Zharkova set five world records under CMAS:

On 27 October 2016, Zharkova became the first Ukrainian and the second woman in the world (after Natalia Molchanova) to dive through an underwater vertical cave known as Blue Hole on a single breath. Zharkova immersed to a depth of 56 meters and then swam 30 meters under the arch.