By listfiles/Kanguole - Own work, based on file:map of Sunda and Sahul.png and usingCoastline from Natural Earth 1:50m Physical Vectors125m depth contour derived from 2-Minute Gridded Global Relief Data (ETOPO2) v2, NOAA National Centers for Environmental Information, using gdal_contour (from GDAL)., CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=127823375
Earliest evidence that hominids took to the sea on boats was from tools and trace evidence left on a rhinoceros skeleton from about 631,000-777,000 years ago, likely to the Philippine island of Luzon, the largest island of the Philippines. At this time, Homo erectus was most likely the voyager. At that time, with the lowered sea levels because of the ice sheets that pushed as far as the 40th parallel in some places, covering maybe 30%, drawing water out of the oceans. While this made it so that many of the islands off of the southern tip of India were joined together, reaching the Philippines would have taken at least a short sea voyage.
It wasn't until about 65,000-53,000 years ago that Homo sapiens crossed what is now known as the Wallace line to reach what is now Australia. The winds at the time would have been favorable for what would have been at least a 55 mile (88 km) journey with no land in sight. Winds would have changed about 58,000 years ago, making the crossing much more unlikely, which points to a single period of colonization of Australia.
By Cat's diary (猫猫的日记本) - Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=34243737
About 35,000-32,000 years ago was the beginning of maritime trade networks as evidenced by Philippine and Wallacea obsidian appearing one nearby islands, though exactly how people traveled by sea isn't know, whether by rafts or dugout canoes. These trade routes likely began by following the coastlines and moving by between line-of-sight islands.
The earliest evidence of whaling appears around 6000 BCE in Korea. Most likely, the method involved many small boats to cut the whale off from the ocean and herding it to land with noise and perhaps arrows.
By Obsidian Soul - Own work, CC0, https://commons.wikimedia.org/w/index.php?curid=75764398
Between about 3000 and 1500 BCE, with the use of catamarans, outrigger ships, and tanja or crab claw sails, the Austronesian people began leaving Taiwan and colonizing islands as far reaching as Easter Island and New Zealand to the east and Madagascar in the west. They also supported a trade network that was the precursor of the Maritime Silk Road, which began in the 2nd century BCE. These trade routes gradually began using the monsoon winds, which would blow in one direction for half the year and switch directions in the other half, making it possible for bulk trading and for the Maritime Silk Road to develop. Maritime trade routes grew safer than overland routes due to a lack of bandits, improved navigation technologies, and lack of 'extortionate tolls by local potentiates.'
By Pavljenko - Own work using:Map first shown in Bellwood et al. (2011) and taken from Benton et al. (2012), CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=116424449
Evidence of the spread of Austronesian people is evident in the languages spoken on the many islands they reached. There are many words that are derived from Sri Lankan or south Indian languages, such as the various words for 'ship' including paṭavu, paḍava, padau, folau, halau, and wharau. Austronesian peoples used advanced navigation techniques, using both constellations and the timing of stars rising over the horizon to navigate. There also appears to have been a 2,000 year pause in expansion, to about 700 CE, when the Polynesian people group moved into the Cook Islands, Hawaii, Easter Island, and Aotearoa, New Zealand.
The Chinese began trading with the Austronesian peoples during the Han dynasty (220 BCE-200 CE), calling them 'Strange Things of the South' (Nánzhōu Yìwùzhì — 南州異物志). Despite this, or maybe because of it, they didn't develop their own navy until the Song Dynasty (960-1279 CE).