Tunnel Drives are, possibly, the most exotic form of FTL travel and not one that many are likely to experience. It is currently limited to military applications.

These drives require a sizable power source and some exotic material that is consumed by engaging the drive. Typically, a flagship in a military fleet would be equipped with this drive; they are often limited to Military City Ships.

The ship equipped with the Tunnel Drive will engage the engine, which opens a one-way wormhole connecting one location to another. The entire fleet can then move into the wormhole at once, and all emerge at the same location in formation. Travel is not instant; in fact, it can be wildly variable with travel sometimes being much longer, or much shorter, than using Ripple Drives instead.

It is difficult to predict the exact time of travel, and it requires an exotic material in order to engage the drive which is consumed with each use, so the use of these drives is quite rare. However, it makes a good strategic deterrent as it can be used to bring an entire combat fleet all at once to a remote destination.