Abstract: Telemetry techniques have been applied to the complex science of fish passage for over 40 years. Over the past decade there has been tremendous growth in the fish telemetry market with new vendors and new products coming online every year. Researchers often wade through a myriad of study needs and telemetry possibilities in the early stages of planning which often include: the geographic study area, water conditions (ambient noise, entrained air), system cost, tag size, fish weight to tag ratio, tag life, tag broadcast frequency, detection range, binary or 3D data, collaboration with other studies, data management and data processing. Sorting through the various products in search of a telemetry tool for a specific project application can be a daunting task. Fortunately, in just about every instance, there are telemetry solutions which may be applied to help understand fish movements in a passage environment (bypass, fish ladder, river, etc…). Fish telemetry can be broken down into a few categories from basic to complex: Radio Frequency Identification Tags (RFID/PIT), radio tags and acoustic tags. Each technology has benefits and limitations. RFID tags, for example, are very small (as small as 8 mm long and can be implanted with a needle) and have a relatively limited detection range. Radio tags have a longer range of detection but tags are also larger and have an external antenna. Acoustic tags have the longest ranges and offer 3D capabilities but tags are larger and often more expensive. In many instances, a combination of technologies may be utilized to meet research needs (i.e. tagging fish with both an RFID and acoustic tag). This presentation will provide an overview of current telemetry technologies and a comparison of the benefits and limitations of each.