TMM EVA pipeline is the gas export pipeline from the Block 18D Gas Field in the Gulf of Thailand to onshore. With 300 MMSCFD it is one of the main gas export lines in the region. In total, 3 platforms feed into this pipeline, two of which feed through a 30o wye piece. Shortly after the last tie-in, the pipeline expands from 24” to 28”. The main challenge is in the inspection of the first tie-in, which results in the following pipeline configuration: Launch into a 70 km (43 mile) 24” pipeline, traverse a 30o angle wye-piece into the 24” mainline, traverse another 30o wye piece in the straight line, traverse a 24” x 28” expansion and run another 290 km (180 miles) of 28” pipeline to the onshore receiver. Pipesurvey International presents the process of engineering-design, simulation, field work and data analysis of this challenging pipeline.