Abstract: One of the main concerns of the welding industry is to develop the talent of its human resources since, the quality and innovation of its products and services depend to a great extent on the knowledge, the ability and the talent that vocational welder worker apply in the welding industry. The core competency defines a set of knowledge, skills and behaviors that professionals must have to affect in their careers. A core competency facilitates the identification of training needs and guides the design of a professional development program. Thus this research was to explore and examine the core competencies in vocational welder worker based on Thai welding industry participator perceptions. To synthesize core competencies first used the focus group technique with 17 experts to identify their perspectives on core competencies in vocational welder worker. After that competencies questionnaire survey was developed to collect data from a participator sample consist of 1,206 welding industry participators. Research methods were applied to collect quantitative data using questionnaires, forms interviews, discussion groups and workshops.