When they were small, before they could talk or read, our children were easy to entertain. Give them a piece of paper and they would be working for hours figuring out how to use it. Unless they started eating it, got hungry, sleepy, or pooped. Usually that happened first, either of those.

When children are a little older, they tend to be more communicative and inquisitive. It is much more fun for you as a parent, but also more work, because they demand to be entertained. Actually what they crave is stimulation, preferably in close body contact with a parent. Small children demand body contact, and they are hardly very independent. They still want mommy or daddy to hold them and help them. As they get a little older, they start becoming more independent, stressing start. Some days you are not even allowed to change their diapers, other days your preschooler will demand to be carried and will not let go when they hug you.

But as a quirk of the international travel system, your children can get free tickets until age of two. The assumption is that they will sit in your lap, of course. So you really want to leverage that, if you can get the vacation. But it means you have to entertain your child during the flight.
While a six month old will be endlessly fascinated by a piece of wrapping paper, her one year old self will have grown up to realize that the gift is more important than the wrapping. And at 1.5 years old, she is able to distinguish between different kinds of presents.

But all children are different. Some will still be fascinated by the wrapping paper. Others will want to draw on it. Occasionally, there are children who will eat it (so use a paper printed with non-poisonous ink). They grow up at different rates and as they develop a relationship with the outside world, those relationships are different between all individuals.
Since you probably did not get a ticket for your child, they will be sitting in your lap. Rather, he or she will be sitting in your lap, since the airlines only allow one child per adult. If you are like me (or even if you only have two children), you often end up with one on each knee. That will work when the fasten seatbelt sign is off, but when it comes on you have to hand one child off to another adult. Minimizing the amount of screaming and kicking while you do this is a bigger challenge than you might have expected before you became a parent.

How to entertain infants varies infinitely with their personality and age. Up to 6 months or so, their favorite entertainment will still be cuddling up on your stomach and listen to your heartbeat. When they are not asleep.
As they get older, the children get more curious, active and demanding. When they are 24 months old you probably have already considered getting their own seat. They will kick the seat in front (because they are too big to sleep in your lap, even if they will try). They will obscure the view of the entertainment system, spill the coffee all over your lunch, sing at the top of their lungs, and have running competitions in the aisles. Until they fall asleep in the space allocated to them - your lap.

In the time between the cuddling up on your stomach and the running competitions down the aisles, they are discovering the world. And that is the key to entertaining them as well as keeping them entertained. You will quickly note that those two things are not actually related, by the way.
As children discover the world, things which exercise their sense of shape, texture and color will help keeping them entertained. The more they are like real objects that you are using yourself, the better it is. At this point, your children are both bonding with you and want to imitate you, so the more real an object is and the more you actually use it, the more attractive it will be. A clip of plastic keys will be much more entertaining than a bunch of paper note cards, regardless of how many zeroes are printed on them.

At that age, it is probably better to bring something that is familiar, at least that they have seen a few times. That serves two purposes: They will not be scared by it (or the circumstances where they got it), and you know that they have tried it and will like it. Or at least liked it the first time. This is why you want to bring more than one toy. But only give them one at the time, otherwise they will be confused.
Or they may play for two hours with the paper cup the flight attendant brought. You just never know at that age. Only be careful that they do not eat it. Take the same precautiotions as with other toys that age - nothing with small pieces that can come off, only non-poisonous colors, that sort of thing. You probably know very well what I talk about.

You may want to be careful with certain toys for another reason as well: They might destroy the airplane.
Yes seriously. Well maybe not poke holes in it, stop the engines, or blow it up. But if you bring something with colors or stickers, which my children enjoyed before they stopped being lap children, you have to be careful. Crayons and coloring pens can stick to the plastic of the airplane interior, and even if it is designed to be an especially ugly color, you do not want to pay for changing the plastic panels. Especially since you do not get to take them home. Or maybe threatening to make you take them home would make you extra careful. Always use pens or crayons which are washable with water.

Also be careful with anything sticky, especially if you are sharing the seat row with other people. There are those who think that you should dress up to travel (or maybe they did not have a choice), and if your child sticks their DrMcStuffin hippo onto someones Dior dress and it does not come off, the trip may end up costing you more than you bargained for. Much more.
Remember to bring plenty of paper, but in notebooks or sketchpads. You do not want loose leaves flying around the airplane, no matter how many zeroes your children have written on them.

At that age, electronics are not a good idea. Especially not on board an airplane. Their eyes are sensitive to the blue light that screens give off, and their ears are too sensitive to handle the sound from earphones. It is very easy to turn up the volume too much, and at that age, causing lasting damage by exposing them to loud sounds is way too easy. Just avoid the potential issues by avoiding electronics in-flight until they around three, and you do not have to worry that you destroyed their eyesight and hearing so they would be quiet onboard.

There are lots of things to do In Tokyo any season. And there are places you want to avoid with children - the hot plate in okonomiyaki restaurants, for instance. It really is very hot. So some of the fun things that grownups do is out of bounds when you bring the kids. But isn't that always the case?
That said, here are ten things you should do in Tokyo with your kids. Even if they are in a stroller. Maybe especially if they are in a stroller. After three years, these are our best experiences.

These are perennial things you can do at any time, even if there are many seasonal events (like watching the Christmas lighting displays). And to be on the safe side, here is a different post with tips to do if it is raining.

Asakusa is worth seeing, but everyone who comes to Tokyo for the first time thinks so too - at the same time. It can be insanely crowded and hard to navigate.
If you have kids in a stroller, avoid the “nakamise” road from Kaminarimon, the gate to the temple area, and take one of the side streets which will lead you to the temple proper much faster.
The temple is an architectural marvel, and getting your fortune told is a fun exercise, although difficult for kids. But there are instructions in English and the fortune is written in English and Japanese. Putting joss sticks in tJapan is, despite its ageing population, a great place to bring children. And Tokyo is particularly welcoming. A throroughly modern train and subway system makes it easy to go literally anywhere with kids in a stroller, and as a benefit to traveling parents, the subway and train stations have clean toilets with excellent changing facilities.
Getting your fortune outside the temple is fun although complicated, and makes for a nice souvenir. Putting joss sticks in the bowl is perhaps less fun, and you will not see the more then two thousand years old statue which was the origin of the temple - it is too holy. And probably too fragile.
If you go to the left as you leave the temple, there is a small playground in front of the store selling Japanese festival goods. Those make excellent souvenirs, but do not leave your kids alone in the playground. Even a fairly big toddler will need some assistance with the equipment.
​Asakusa is a tourist destination, but on the back streets it is a part of Tokyo you would not want to miss. Here you can find craft shops that have been doing things the same way for several hundred yeats, often originally for the samurai armor and swords. And there are stores selling sweet potato and beni-imo soft icecream. Delicious, despite what you may think. Take time to explore. It is worth it, as long as you do not drop into the first shop selling something that looks typically Japanese - it is likely to be a tourist trap.

The restaurants where sushi is served on a conveyor belt are one of the most famous features of modern Japanese cuisine. In central Tokyo, the restaurants are mostly oriented towards an audience eating fancy dishes and drinking beer. You do not have to go far outside the city center for these restaurants to change character and become much more family-friendly, and a fun experience both for the kids and the parents. And even if there are some which serve breaded and deep-fried shrimp, there are a lot healthier alternatives for your kids.

The second tallest building in the world (it was the tallest for a short time) is located in Tokyo. The Tokyo Sky Tree observation platform is actually only two thirds up the height of 648 meters, but still much further up than most other buildings of Tokyo.
​That is actually a problem, since you really do not see the view from that far up. It is more fun to go up the Sun City tower, or the towers of the Tokyo Metropolitan Government Office, or the Mori Tower in Roppongi. You will see more of the view since the details do not disappear in the background. And it is much cheaper than the SkyTree - free in most cases.

Park the stroller at the front window and your child can marvel at the feeling of sitting in the drivers seat of an rushing train. Only there is no driver.
Odaiba, which is built on artificial islands created by filling up the mudflats that used to border Tokyo Bay, is still growing as Tokyo keeps producing more and more waste, although this is not a landfill. But new land is created every day, and of course this new land is built up with new buildings. Some of them sufficiently futuristic that you start waiting for cat robots to jump out of translucent portals.
Odaiba is also an entertainment and shopping center - this is one of the few places where there is sufficient space to do something outdoors. The cosplay people dressing up as various characters in their favorite animated movies have moved from Harajuku (where it is too crowded) to Odaiba.
The futuristic buildings and open spaces create a combination that make you feel like you indeed are in some kind of future version of Tokyo, and the sunsets in Odaiba can be gorgeous. Walking through the grassy park paths is a really uplifting experience.
​If your child is a little older, by the way, you do not want to miss the Panasonic showroom. It has a lot of discoveries to offer. For free.

If you have an image of Tokyo, it probably contains robots and high-tech. While you can order sushi from iPads and talk to robots in mobile phone stores, high tech is not as much a part of the everyday Japanese life as people might think. Huggable seal robots, trainable dog robots, and cat robots with built-in takecopters are still things of the future.
Except at the Miraikaikan in Odaiba. This is where the futurists of Japan come out of the woodwork and show off the vision of what society will be lke when we have cat robots eating our dorayaki.
But it is not a museum that presents a full-fledged vision, even though the Japanese government keeps publishing them. It drills down into the inner workings of the technology behind robotics, solar cells, electric cars and other things which are not part of the future but everyday in Japan anymore.
It is a fun museum for grownups, and for children with more than a minimum of sense of wonder. If you are going to Odaiba, it is worth the stop.

One of the most famous exports from Japan is the Japanese garden. There are Japanese gardens in many places around the world, but of course there are more in Japan.
The garden style of Tokyo and Kyoto are different; Kyoto gardens are temple gardens, which are intended to create a sense of serenity without words. Tokyo gardens are strolling gardens, originally attached to the palaces of the daimoyo, the regional chiefs forced by the shogun to keep their families in Tokyo. So of course the purpose was very different; these gardens were intended to serve as a combination of strolling gardens for the families held hostage and secret meetings of samurai plotting to move themselves or their master one step up in the world.
Of course, in those days nobody had strollers. But they had very tall shoes and long flowing kimonos, so the paths of the gardens (at least the one where the ladies would have walked), so these gardens are usually easily accessible with a jogging stroller.
There are several of these gardens in Tokyo, painstakingly recreated from the originals after WWII, when the plants and trees were mostly burned cinders. One of the most charming is the Koshikawa Korakuen garden, just behind the Tokyo Dome entertainment complex. The entire area used to belong to the Mito clan, who were closely associated with the Tokugawa shoguns.
Now this garden, which is especially worth visiting in cherry blossom season or autumn, when the fall colors make the garden glow with color. But the garden is also worth visiting at the end of February, when the ume, the Japanese apricot, flowers. You might have tried them - the salty red fruits you get in onigiri and with rice. The flowers are reminescent of cherry blossoms but the trees look more like dragons crawling across the ground. Try some amazake, the raw Japanese rice wine, which is just sweet (not fermented yet, so no alcohol)and usually served piping hot. If you give it to your children, careful since it may contain half-melted rice grains that they could choke on.

In a city like Tokyo, finding a temple without tourists is as rare as a sunny day in Dublin. But while most of them throng to Senso-Ji in Asakusa, there are many hundreds, if not thousands, of temples across Tokyo.
Among them, Gokokuji stands out. Not because it has a remarkable reliquary or because parts of it has been designated as important cultural properties by the Japanese government. It stands out because it is not reconstructed, like almost every other building in Tokyo.
Tokyo was mostly a smoking ruin after the second world war. The fire bombings caused huge devastation in a city that at the time mostly consisted of wooden buildings. That added to the devastation of most Western-style buildings during the Great Kanto Earthquake in 1923. The city after the war was literally a field of debris, with a few buildings standing. Like Gokokuji.
The temple sits between a cemetery and a university campus, which helps making the area serene and also makes for great walking paths, as this is not a traditional Japanese cemetery but a Western-style one. It is worth a visit itself, especially a fine day with a stroller.

Tokyo is a harbor city, and as it was built on a swamp, it has canals and rivers running through it. Most of them are actually underground now, but they all run out into the sea in Tokyo Harbor.
Since there are so many rivers running out into the Tokyo Harbor, you might expect Tokyo to have plenty of sightseeing bosts running up all those rivers and canals. But since most of them are no more than glorified sewers in reslity, you would not try to take a boat up one of them.
But there are great sightseeing tours on the proper rivers of Tokyo. The biggest river running into the Tokyo Bay is the Sumida River, which starts out as the Arakawa river and then picks up various tributaries, including the Arakawa river and the Kanda river.
From there, the river travels downwards past Asakusa, which is where you board the cruising boat. The boat, which will take you you from Asakusa to Odaiba. There are unfortunately no cruises from more central destinations, since they over the years have moved further out into Tokyo Bay. Once, it was actually possible to sail an ocean-going ship up to what is currently the Yaesu exit of Tokyo station. That was 400 years ago, and in the meantime the entire Ginza and Odaiba districts have been created out of nothing, or rather the mud flats which used to cover Tokyo Bay at low tide.
The boat cruises down the Sumida river, and takes a turn through Tokyo Bay, but there are several lines and if you want to see Tokyo from the water, combine them. They only have Asakusa in common, however.
The boat is designed by Anime Lejime Matsumoto and covered so you do not have to be afraid of your children falling overboard.

It used to be that when Japanese developers planned a shopping mall, the first thing they put in was the Ferris wheel. Today, you have one in Odaiba, and another in the Tokyo Dome amusement park, connected to the Tokyo Dome indoor arena. That park also has a rollercoaster that runs through a shopping center, although that is not for your toddlers.
Apart from the Tokyo Dome amusement park, there is an amusement park in Asakusa which has operated continously for more than 150 years. Located in the middle of the tourist district, right among the shops selling kimonos and icecream, Hanayashiki is not quite what you might expect. It is probably the smallest amusement park you will ever see, but it has a lot of attractions folded into the minimal space and from the inside it feels much bigger than when you see it from the outside.
The problem with Hanayashiki is that thanks to the size, it is hard to get around with a stroller. An umbrella stroller might work but there are very few attractions that an infant can enjoy, even accompanied by their parents. There are not many attractions suitable for toddlers either.
You may be better off trying a third park, either in summer or if your infant is properly bundled up, in winter. Toshimaen west of Ikebukuro is fairly big as amusement parks go, even outside Japan. It is designed not just to provide amusement but also a beauty experience. Not only is the park designed to be good for walking around. It is also a great spot to see cherry blossoms and the autumn colors, when the trees shift their leaves in fall. But apart from toilets being somewhat scarce, this is the best park to visit with both infants and toddlers. 

Japan has five pronounced seasons (the usual four plus the rainy season, which feels much like the southeastasian monsoon). Each season has its traditional highlights, except the rainy season. But watching the cherry blossoms in spring, or the fall colors when trees shift to red and yellow and orange, is a completely different experience from your everyday walk in the park. And if you can navigate the crowds, it can be experienced from a stroller as well.