Tickets are usually booked on-line. Check for "Red tickets" or "Last minute offers" for cheap cruises to Stockholm.

If you intend to use the ships to travel between Stockholm and Helsinki or Tallinn it is almost always cheaper to book a round-trip cruise (Swedish: kryssning, Finnish: risteily), or even two head-to-head cruises and discard the returns, rather than buy one-way tickets. Tickets can often be had for as low as €10/80 kr for a full 4-person cabin on a two-night Stockholm–Helsinki return cruise, making it practically the cheapest accommodation one can find in a high-income country – provided you book early or last minute during the weekdays. The cruise price rarely (even for a weekend cruise in high season) exceeds €50/400 kr for the cheapest 4-bed cabin, while a single berth in a cabin shared with strangers, one-way from Stockholm to Helsinki or Tallinn, in comparison, usually exceeds €125/1000 kr.

As the Baltic Sea is rather small, swell dies down in a day or two, so the sea is rough mainly when the wind is strong. Many of the Baltic ferries are very large, with stabilisers to reduce rolling, so rolling is gentle except in very rough seas. On the other hand, if there is a storm, restaurants are often closed, as serving the few that still want dinner is not profitable. The situation is different on the ships not serving cruise clientèle.

In January–March sea ice affects most shipping, but the large cruise ferries and the ROPAX ferries on Northern Baltic routes are built for icy conditions. Sea ice may result in delays but cancellations are rare. The Southern Baltic is much less affected by ice.

For overnight cruises, the ticket price is per cabin. A regular cabin accommodates four passengers, holds a standard comparable to two-star hotel room (toilet, shower, soap, towels, reading light), and is much cheaper than a hotel room in Stockholm or Helsinki. The cheapest (C-class and some of the B-class) cabins are on the lowest decks and have no windows, while A-class and above have window views either facing to the sea or to the interior space. At the upper end of the scale, high floor suites can offer panoramic ocean views and perks like access to dedicated lounges. Some ferries return immediately and you might have to spend some time ashore before the destination city awakes.

The ferries between the Stockholm and Turku regions have very tight schedules with just an hour in port, which means cabin cleaning begins very early (unless you have a return ticket). Do not count on being able to sleep until just before the ferry arrives. In summer (with early sunrise) waking up for the pricey but plentiful breakfast and watching the huge archipelago while approaching may be a good option.

If crossing the Northern Baltic in winter, check the cabin location, as going through ice causes quite horrible noise for those most affected. The season with sea ice on the Tallinn/Helsinki/Turku–Stockholm routes is mostly January to early March, varying by location and year; there are maps on the extent of the ice cover.

When travelling between Helsinki and Tallinn during the day, the trip is so short (about two and a half hours) that a cabin is not needed, you can just pay for the trip itself and stay on the decks for the whole trip.

Most cruise ferries have several cafés and restaurants at all price levels (although the budget options will not keep your hunger away), at a standard typical to Sweden and Finland; you know what you get, but you won't be impressed. The most famous one is an all-you-can-eat Nordic buffet/smörgåsbord at around €45. Should traditionally be eaten as seven servings; herring, other seafood, cold cuts, warm meat, sausage, cheese and dessert.

For booked tables when your origin and destination are in different time zones (eg. Tallinn to Stockholm), inquire in advance which timezone is used, as it usually is ship's time that counts, not the actual timezone, even if called "local time". Typically the timezone at the port of departure is the timezone used on the ship.

Drinks in the bar are slightly cheaper than in regular Swedish or Finnish pubs, although expensive compared with the ones in Estonia, Latvia and Russia. Cocktails start around €8.

On some party cruises, alcoholic beverages may not be brought on board. The crew might search passengers' luggage for them. St.Peter Line actually x-rays your luggage to look for alcoholic beverages when boarding as a pedestrian. Any such bottles will be taken away, you'll get a receipt and get the bottles back at the information desk the next morning half an hour before arrival.

The cruise ferries have performances, karaoke, troubadours, live dance music, discos, bars and nightclubs. Check the cruise program.

Most cruise ferries between Sweden and Finland make a stop at Åland, to earn the legal opportunity to host duty-free shopping (as Åland for tax purposes isn't part of the EU). These stores, with alcohol and tobacco prices far below Swedish and Finnish levels, are the main attraction for many passengers. Consumption on board is officially not allowed, but happens all the time. At weekend party cruises, these stores do not sell alcohol during the evening. Also cruises to or from Russia have duty free shops, although much smaller ones.

The stores also offer the classic duty-free supply of perfume, make-up and sweets. Some ships also have shops for clothing, toys and other consumer goods. Know what you'd pay elsewhere if looking for bargains.

Ferries accept credit cards, and at least local currencies (in most cases euro and Swedish krona). Payment by Google Pay / Apple Pay (and PayPass / Visa PayWave) is frequently not accepted on Tallinn-Stockholm ferry by Tallink.

• Dancing to live music, nightclubs, karaoke, disco. The clientèle and performers vary depending on time of day, day of week, departure port and time of year.
• Gambling at slot machines and roulette tables. If you do this, keep to your budget even if the net income – at least on ships with the Finnish flag – is distributed to good causes.
• Most cruises have free play areas for children with ball pits, climbing gyms, game consoles etc, as well as a rotating schedule of activities.
• Sauna. Separate for male and female, so no bathing suits are needed there. Some ships also have a common area, with a hot tub or a pool, and perhaps Turkish sauna (hamam). The entry fee is around €7.
• Sunbathing on the upper deck, if the weather allows.

Elevated view of e.g. the Stockholm archipelago, Åland and the Finnish Archipelago Sea (depending on route). Stage performances nightly and often now and then also in the day.

Ship safety is serious business on these ships, with experience from the M/S Estonia disaster in 1994.

Do not enter restricted areas. Avoid the open deck at night and in harsh weather. Smoking is only permitted in designated areas.

Drunkenness is common on these ferries at night, and differences in languages and manners often provoke conflicts. While security guards tend to forgive drunkenness, they will lock violent passengers in a cell for the rest of the journey, or even put them off the ship at the next port.

Cabin parties are common, but security will respond if neighbours complain.

For safety reasons, avoid going alone to strangers' cabins. If something nasty happens, do report it as soon as possible – police will probably meet in port.

On most cruise ferries, Wi-Fi is available at least in common areas and higher-class cabins throughout the trip, accessible through individual passwords printed on each passenger's ticket or from reception. The connections may be slow and sketchy though, with data-intensive applications blocked (to maintain a fast connection to the shore is very expensive). Mobile voice and data connections are good when in the archipelagos or otherwise close to the shore, you may prefer a cabin with a window to get a better connection.

Most of the cruise ferries have playing rooms for children and children's cruise programs, some have separate entertainment rooms for older children and youth. Also some of the mostly-trade ropax ships have some facilities for families with children. Check with the company about arrangements provided. Consider to what extent you want to expose your children to playing machines and drunk co-passengers. You might want to avoid certain areas if you are up late. You may be able to choose a cabin in a quiet corridor.

Saint Petersburg cruises include time in town. Cruise passengers are exempted from visa requirements (check the terms).

A 40-hour cruise Stockholm–Helsinki, Stockholm–Tallinn, Stockholm–Riga or vice versa includes an 8-hour stop in the destination city, enough for visitors to make a short tour.

Between Stockholm and Turku returning with the same ship means 23-hour cruises, without time ashore.

The pass over Gulf of Finland is short enough to give time in Helsinki or Tallinn, if taking a morning ferry and returning in the evening.