Subsea cable technology has been around for quite some time. The first successful trans-Atlantic subsea cable was laid in 1866 and carried telegraph signals. Burying subsea cable and pipe to protect it has become much more common in the last four decades. Many tools have been engineered and used successfully to install and maintain telecommunications (telecom), oil and gas (O&G) pipe and power transmission cables (Offshore Wind and inter-connectors).
Likewise, many alternative methods and products have been developed for subsea cable protection, tailored for a range of scenarios. These types of custom fit site specific protection measures are all generally much more costly than cable burial. Given the enormous distances that protection is required, the most cost-effective approach is usually to bury cable and pipe with specialized burial equipment.
Since it may be hard for people to visualize how burial is done, we have included a few helpful videos (directly from youtube.com) created by some service providers.