During the 1790s, emigration from Europe, especially Great Britain, increased, while conditions of transport deteriorated as older, unseaworthy ships were pressed into use. Often timber ships with no return cargo, ill suited to transport humans, were the primary means of emigration. Vessels were all too often overcrowded, and unsanitary conditions prevailed. The flooring of the ships was usually of poor quality, and numerous rats lived aboard. Public opinion encouraged governments, especially that of Britain, to begin regulation of the shipping companies. The first was the Passenger Vessel Act of 1803, which had been created to protect Scottish Highlanders from the supposedly unscrupulous migration agents. This act restricted the number of passengers that each ship was permitted to carry. It was also required that a surgeon be present on each ship, and that every vessel carry adequate supplies. In reaction to this act, ship owners immediately raised their rates, effectively eliminating the option of emigration for many of the poorest Old World inhabitants. Despite regulation by European governments, the situation improved only marginally. Conditions were still overcrowded, especially for children, who were considered to require half the space of an adult. Mortality on these voyages was especially high for the young. The terrible health conditions of those arriving in North America prompted Lower Canada, Nova Scotia, and New Brunswick to collect a small surcharge per immigrant in order to provide money for the care of the very ill. In the 1850s conditions improved greatly with the advent of the steamship.

From 1845 to 1848 the Great Famine in Ireland resulted in 85,000 émigrés to North America in 1847 alone. This massive demand for trans-Atlantic shipping meant that once again old and unseaworthy ships were pressed into service. These ships, termed "coffin ships", were often unsanitary and unsafe. Many sank during the course of the voyage, and typhus and dysentery beset passengers. Most of these ships landed in Canada, where the surviving passengers were sent to the quarantine station at Grosse Isle. During 1846 and 1847, 30,000 people died from disease in transit between Europe and North America.

For the vast majority of earlier migrants, the voyage to the New World would be a long, tedious journey in the steerage of a trans-Atlantic sailing ship. There were some general rules of conduct aboard ship; lights were to be out at nine or ten p.m., single women were to be chaperoned by married ones, male passengers sometimes served as night-watchmen, and so on. The passengers often amused themselves by dancing, gambling, or talking. Many brought their own supplies for the voyage; in other cases the shipping company supplied provisions. In the early years, the latter meant that the adult passengers were usually supplied with one pound of bread or cornmeal daily. After state regulation had been applied to shipboard conditions, the diet of most passengers improved considerably, now including soup, rice, raisins, and tea. One of the main problems facing both passengers and crew was an adequate supply of fresh water. It was often impossible to clean oneself or one's clothes for the entire duration of the voyage. The water available for drinking was often dirty and malodorous from storage in casks. However, the most central difficulty of the trip was overcrowding and illness. There are numerous accounts of conditions on these ships. One states:

"…the between decks were a loathsome dungeon. When the hatchways were opened under which the people were stowed, the steam rose and the stench was like that from a pen of pigs. The few beds they had were in a dreadful state, for the straw, once wet with sea water, soon rotted, besides which they used the between-decks for all sorts of filthy purposes." (Guillet, p.72)

Medical supervision was also often lacking on these ships. Often many of the passengers were seasick and were incapable of acting to improve their condition by venturing onto the deck. There was also a complete lack of privacy, something that made use of the latrines difficult for many passengers. The generally unsanitary conditions furthered the spread of disease and contagious illness. The passengers were plagued by cholera, dysentery, small pox, measles, and 'ship fever'. Some years, such as 1847, were particularly bad for high rates of mortality. The average death rate in that year was a total of 16.33 per cent, including deaths in passage, in quarantine, and in hospitals. Shipboard life for the upper classes was drastically different.

Less than two per cent of emigrants travelled cabin class to the New World. Cabin accommodations often varied greatly from ship to ship, but were always considerably superior to the conditions endured by steerage passengers. Meals of reasonable quality were often provided, some privacy was available, and, of course, overcrowding was much less. A noticeable class distinction existed between steerage and cabin passengers. Those in steerage were termed 'emigrants' while the cabin class were 'colonists'. These upper class voyagers entertained themselves during the trip by presenting plays and mock trials, organising debating and choral societies, and playing quoits, deck billiards, cards, dominoes, draughts, and backgammon.

Regardless of the conditions for passengers aboard ship, all vessels faced some common dangers. There was the constant threat of fire, which was a disaster for a ship at sea. Shipwreck was also a possibility. The smaller ships even faced the danger of being attacked by whales. Any of these occurrences furthered the risk of epidemics and starvation.