Unlike leisure diving, commercial diving refers to the entire techniques involved in underwater or seabed exploration using diving equipment for the purpose of marine development. Commercial divers work in the ocean, dams or rivers. The formal title of the job is industrial diving engineer. Commercial divers are involved in the research of underwater objects, which consists of examining the condition, capturing images and collecting samples of the objects; installation and repair of facilities such as underwater pipelines and optical cables on the ocean floor; and salvage of sunken ships and refloating stranded ships. In addition, commercial divers' jobs also include life-saving; removal of oil in the event of marine pollution; installation of pillars that support bridges; dock or seawall construction; construction of cooling facilities for thermal and nuclear power plants; and dredging operations for port (digging out sands or mudflats). Their job requires technical knowledge in underwater photography, underwater welding and cutting, underwater blasting, and underwater engineering. Consequently, commercial divers must be certified in these relevant areas. As divers are always exposed to risks working at great pressure with increasingly complicated equipment, certification ensures the selection of divers who can meet the technical and safety demands of this challenging occupation. The exam is administered by the Human Resources Development Service of Korea once a year. In a field test, competency in diving site management and diving operation is evaluated. In 2007, only about 17 % of the applicants passed the exam, which demonstrates its difficulty. The Commercial Diving Department of Korea Polytechnic College III in Gangneung Campus is the only training class in Korea. Korea Commercial Diving Technician Association provides short-term educational courses for acquiring the certificate.

To acquire a leisure diving license, he/she must be over 15 years of age (ages 12 to 14 are recognized as Junior Scuba Diver), and receive 14 hours of theoretical lessons and 17 hours of field lessons at a leisure diving training institute. As a trainee, he/she should receive at least five on-site classes (including 1 scuba diving class) and must be able to swim 200 meters regardless of swimming style, stay afloat for 10 minutes (survival swimming), and swim 15 meters underwater. Once the basic courses are completed, the trainee is allowed to participate in open water diving activities independently without a supervisor. As such, one needs to familiarize him/herself with beginner, intermediate, and advanced levels of marine leisure skills and acquire a license at a master's level to become an instructor. In the case of leisure diving instructor courses provided by the Korean Underwater Diving Association (KUDA), the levels are in the order of assistant instructor, instructor, master instructor, and instructor trainer. After completion of the Instructor Training Course (ITC), he/she becomes an assistant instructor and when they pass the final test of ITC, they finally become an instructor. Once an instructor, one can open a leisure diving center on a beach and operate a diving resort, while providing leisure diving training and boat and equipment rental services. Around 600 such centers are known to be operating in Korea.

A leisure boat is a name given to all watercrafts manufactured and used in marine leisure activities such as yachts, motor boats, and jet skis. A license is required to drive them and a leisure boat operating trainer provides such training for acquiring leisure boat license, just as a driving instructor gives driver's license training. To work as the license instructor, he/she needs a license him/herself. The license test is held in leisure boat exam sites in Seoul and Busan, etc. 1st and 2nd class leisure boats and yachts are subjects on the exam. To drive leisure equipment greater than 5 horse power, such as a motor boat or jet ski, he/she must hold a 2nd class recreational powerboat operator's license. Furthermore, to do business in the water leisure field, he/she needs a 1st class operator's license.

Many people in the fishing villages operate a fishing boat business as a vocation. When we look at advanced countries, such business gradually has become quite sophisticated with the introduction of professional leisure fishing businesses. There are also many cases where non-fishermen who own motor boats start leisure fishing business. As the five-day work week has fully set in and people's interests over leisure activities have grown, there will be more demands for the business. If one wishes to start an ocean leisure fishing business with the operation of a vessel, a leisure boat operator's license is required. When operating more than one boat, he/she may hire other license holders to operate the vessels.

A marine environmental education instructor is an environmental education specialist in the field of marine protection areas and mudflats. In particular, these instructors provide marine nature experience classes on mudflats and migratory birds for elementary, middle and high school students in wetlands or coastal areas are called "eco-tour guide." Eco-tour guides satisfy the ever-increasing demand for mudflats ecological expeditions, while at the same time, providing accurate knowledge on mudflats and migratory birds to prevent destruction of coastal wetlands, thereby teaching ecology. In each region, yearly training sessions for the mudflats eco-tour guide are held in tidelands and coasts. The current state of mudflats and their functions, ecology in mudflats and the wise use of these resources are taught to foster guides who will raise awareness of the value of the mudflats as a precious natural heritage. In addition, a professional program is offered, which comprises of lectures and on-site classes on general understanding of the ecosystems of mudflats, migratory birds, benthic organisms, and halophilic plants grown in mudflats, as well as classes on the need for ecological education, their methods and principles. These training sessions are held by regional sea grant, environmental groups, and district offices. In particular, classes specifically related to mudflats are offered by regional coastal environmental groups or regional organizations. The Ministry of Oceans and Fisheries plans to introduce a mudflats eco-tour guide certification program, which will grant benefits almost similar to a formal license.

A marine mammal trainer rears, manages and trains marine mammals to perform for an audience. They are called dolphin trainer, sea lion trainer, etc., depending on the animal they train. A marine mammal trainer checks on the health of their mammals to prevent disease, feeds them, exercises and care for them. Few people have greater knowledge and experiences regarding their mammal than they do. A love for animals is absolutely essential for this profession. Since neither an instructor's course nor a certification program is offered in Korea regarding animal training, one must be trained in a zoo. Trainers visit other zoos or travel abroad to design new shows. In Korea, there are around 30 marine mammal trainers who work in places such as Seoul Grand Park, Everland, 63 Building Aquarium, and Jeju Marine Park.

An aquarist is a trained individual who raises, cares for and manages marine life. They are also known as marine life specialist or aquarium manager. Aquarists protect, observe and research marine life, and maintain the aquarium to be as close-to-nature and ideal as possible for the healthy living of the creatures. An aquarist's day begins with checking on the fish and the various filtration systems of the aquarium. He/she carefully observes the condition or any particular state of fish, maintains oxygen tanks and fins required in aquarium operation, and examines pumps that provide water to fish and water quality monitoring system. They remove stains on sands or rocks inside the aquarium and clean the acrylic window of the aquarium so that aquarium visitors can see the fish clearly. They feed the marine life keeping the characteristics of each species in mind, and if any fish is found sick, they are moved to a quarantine tank to identify the cause, and medicine is prepared and mixed in the feed. In the case of marine mammals such as otters, veterinarian may be called to operate surgery. Once the aquarium hours are over, aquarists clean up the wastes of the fish feed and keep a daily log regarding any sick fish and what measures have been taken. Aquarists were first introduced in Korea in 1980s together with the introduction of mega aquariums, and there are around 50 of them as of today, who mostly work in 64 Building Aquarium, COEX Aquarium and Busan Aquarium. In the case of foreign companies in Korea, aquarists first enter the company as a junior aquarist, and are promoted in the order of senior aquarist, assistant curator, and curator. Normally, once you become a curator or a head of a team, you will undertake planning and management roles such as planning an exhibition. There is no restriction regarding the undergraduate major or a need for a certificate in becoming an aquarist. Usually, an academic background or high school diploma or higher suffices and most aquarists acquire skills through fieldwork experience. Diving and swimming skills are helpful and fisheries and maritime-related certificates such as aquaculture engineer or fish pathologist are advantageous. Aquarists are in frequent contact with water which may lead to eczema and respiratory troubles. Basic physical fitness is necessary as he/she may need to transfer marine life or carry heavy loads such as rocks to create ecosystems within large water tanks. He/she may need to work on weekends depending on the work schedule, and monitor the conditions of marine life until late hours.

A cruise tour conductor is a travel guide who takes the passengers through entire voyage from the start to end of the tour on a luxury boat. Today, cruise ships are normally built at a 100,000 ton scale and are equipped with advanced equipment and safety systems so that passengers hardly feel any discomfort such as sea-sickness, and are able to enjoy a safe and pleasurable voyage. The cruise ship itself may be thought of as a world's top class hotel. Within a cruiser, all cultural entertainments such as the world-class shows and cuisine, sports, movies and accommodation may be enjoyed like onshore. Moreover, cruising around the natural tourist destinations such as the world cultural heritage sites in the Mediterranean Sea and the Caribbean Sea and Alaska are exotic delights that cruises alone can offer. The cruise industry involves many careers. In fact, there are numerous specialists who work on a cruiser including maritime officer, chef, and casino dealer, but acquiring such a job is not easy since Korea has no cruise ship company as of yet. One cruise-related profession found in Korea is a Cruise Tour Conductor, T/C for short. Cruise T/C, in essence, is a cruise tour guide. Should you wish to tour around the oceans of the Mediterranean, the Caribean and Alaska on a cruise, you must first fly to the place and board a cruise ship, and therefore, it is difficult to use the foreign cruise ships due to their language barriers and lack of knowledge in the local environment. A cruise T/C is there to guide the passengers' entire trip so that they could conveniently enjoy cruising abroad by accompanying them from the very start at the airport. He/she processes immigration procedures, helps passengers use the cruise facilities and also provides simultaneous interpretation services. A cruise T/C usually belongs to a travel agency or works as a freelancer. There are approximately 20 to 30 T/C in Korea. Though cruising has yet to become a popular in Korea, the number of cruise tourists is increasing and thus the job of T/C is likely to see an increase in demand. Unlike a travel guide, a cruise T/C can plan a cruise item him/herself and head a team of tourists. In Korea, many cruise T/Cs envision starting a cruise travel agency of their own in the future, which would be possible once they gain sufficient experience. A cruise T/C is not an easy job if he/she has never led a group of tourists abroad. To become a cruise T/C, he/she must have a high level of English competency and have basic knowledge in travelling, tourism, and customer service. Once all these requirements have been met, they could enter the travel companies in Korea that specializes in cruise items such as Santa Cruise, Hana Tour, Lotte Tour and Hanjin Tour and begin their career as a cruise T/C. In addition, taking a tourism related course established in Sejong University or Kyung Hee University, or Tour Cruise Attendant Course in Daekyung University is helpful.