Robust pipeline tracking is critical for AUV technology to succeed in the commercial sector. This paper presents two techniques for reliably detecting and tracking pipelines using multi-beam echo-sounder and side-scan sonar systems. Because of the specific nature of the problem, a lot of prior knowledge can be used. Our algorithms use a model-based bayesian approach. They are both efficient and robust to variations of the model and noise. Results are shown on real data sets in both cases. The algorithms are compatible with real-time implementation.