Purpose: Analysis of non-destructive testing systems polymer composite in terms of current solutions in the area of methodology and devices. Analysis of contemporary standards for non-destructive testing of polymer composites established by ASTM. Analysis of Flir ONE camera capabilities in non-destructive testing composite carbon-epoxy composites. Design/methodology/approach: The thermal imaging tests of the carbon-epoxy composite discontinuity were carried out using a thermal imaging camera and Flir One accessory for an iOS phone. The tests were performed on carbon-epoxy composite samples measuring 100x100 mm. In order to simulate the discontinuity in a sample by the Resin Transfer Molding (RTM) method, a 30x30 mm PTFE film was inserted between the reinforcement layers. The thickness of the sample with discontinuity was 2 mm. Water was added to the selected sample sites. Samples were placed on a 50°C heated plate to record thermal images and thermal images combined with visual contours of samples with simulated defects. Area Calculator – SketchAndCalc Icalc, Inc. was used to describe the size and location of the defects. Findings: As a result of the tests, the use of the Flir One thermal imaging device in epoxycarbon composite discontinuity tests has been demonstrated, and a methodology has been proposed to measure geometrical features of defects. Research limitations/implications: The description of welded joint structure and mechanical properties was based on welding toughened steels by using an innovative welding method and a filler that has been proposed. Practical implications: The development of thermal imaging studies of polymer composite discontinuity using the Flir One thermal imaging camera and accessory with iOS opens up the possibility of conducting a basic inspection of composite materials in production plants, and even for simplicity – also in small laboratories. Originality/value: In order to improve the quality of imaging of small items using the Flir One mobile camera, the use of cheap and readily available lenses used in laser optics has been tested positively.