Sonar

The sonar is a tool used to detect and display the locations of Fossil Rocks. It is only usable in Dig Sites.

Fossil Fighters and Fossil Fighters: Champions
In Fossil Fighters and Fossil Fighters: Champions, the sonar is a circular display on the upper screen. Players can sweep the area around them using the sonar by pressing the L or R button. The sonar will beep when it passes over a fossil rock and briefly display the rock's location as a diamond-shaped blip. The sonar can detect other objects as well - miscellaneous items of interest, including odd wells, are displayed as red X marks, and in Fossil Fighters: Champions, rare fossil rocks (dark, Wondrous, and Miraculous Fossil Rocks) are displayed as gold circular blips.

Upgrades
Initially, the sonar has a small display, frequently detects nonfossil rocks, and is only capable of locating head and body fossil rocks, but the player can purchase upgrades from the Fossil Guild to enhance its capabilities. The sonar has three components that can be upgraded: The sonar can also be upgraded by progressing through the main storyline, allowing it to detect objects such as Caliosteo Slablets and Sub-Idolcomp pieces. These upgrades are free of charge.
 * Fossil Chip: The Fossil Chip allows the sonar to detect rocks containing new fossil parts. Fossil Chip 1 costs 10,000G and allows the sonar to detect head, body, and arms fossils, and Fossil Chip 2 costs 35,000G and allows the sonar to detect all four fossil parts. In Fossil Fighters: Champions, upgrading the Fossil Chip changes the color of the Normal sonar cover; Fossil Chip 1 changes the cover to gray and green, and Fossil Chip 2 changes the cover to orange.
 * Fossil Filter: The Fossil Filter makes the sonar detect normal rocks less often. Filter 1 costs 5,000G and makes the sonar detect normal rocks slightly less often, and Filter 2 costs 8,000G and prevents the sonar from detecting normal rocks entirely. In Fossil Fighters: Champions, upgrading the Fossil Filter adds additional displays to the right of the main; Filter 1 adds a rectangular display that has different activity levels depending on how close the player is to a fossil rock, and Filter 2 adds a round display that flashes when the player is very close to a fossil rock.
 * Monitor: The Monitor displays the locations of fossil rocks. Upgrading it increases the size of the display and the detection range of the sonar, allowing the player to see more fossils with each scan. Monitor Upgrade 1 is 800G and slightly increases the monitor size, and Monitor Upgrade 2 is 3,500G and fully increases the monitor size.

Sonar Covers
In Fossil Fighters: Champions, the sonar's cover is customizable, and the player may obtain a variety of covers by completing sidequests. The player can change their sonar cover by talking to Sonia Carver in Cranial City's Fossil Guild. The appearance of the Normal sonar cover is determined by the number of Fossil Chip upgrades the player owns, and the player cannot switch between the three versions.

Fossil Fighters: Frontier
In Fossil Fighters: Frontier, the Fossil Sonar no longer has individual components - instead, there are ten separate sonars. The basic Fossil Sonar is available once the player gets a Bone Buggy, and the four other normal sonars can be purchased in the Garage. Each upgraded version of the basic sonar allows the player to discover new fossils. EX versions of each level of the sonar can be won by completing the 1★-5★ tournaments of the Seven Scramble Barnum Cup. The EX Fossil Sonars display data of fossils that haven't been excavated yet - players can check what element a fossil is, what Vivosaur it belongs to, and what part it is. Players can switch sonars in the Garage.

Unlike in the DS games, the Frontier Fossil Sonar displays data on fossils before the player cleans them. Nearby fossils are automatically displayed on the area map on the lower screen and in the Dig Site itself on the top screen as triangular icons. When the player is close enough to them, they will become dinosaur skulls on the lower screen, and if an EX Fossil Sonar is equipped, the skulls will be colored to match the element of the fossil. Triggering the sonar with the L button when near one of the icons focuses the screen on the location of the fossil and displays detailed information about it. The player can use the D-pad to switch between multiple fossils if there is more than one in the range of the sonar.

Frontier also introduces Challenge Routes, which players can complete to earn rare fossils. Different levels of the Sonar are required to find different fossils.