Depending on which cruise line you choose, your ports may vary. Here is a list of the most popular ports, and what to do at each.

Juneau - Alaska's capital

A picturesque mix of snow-capped mountains and glaciers. This port will be on any itinerary. As far as shore excursions go, Mendenhall Glacier is a must. You can hike it, do a helicopter ride to it, and even dog sled on it. If you're looking for something a little bit more relaxed, Juneau is the spot for whale watching. It isn't uncommon to see dozens of whales during a 2-3 hour boat ride. On top of seeing the whales, the coast line scenery is pretty stunning in itself. For food check out Tracy's King Crab Shack or the Red Dog Saloon.
Skagway is another popular port on 7 day sailings, and a personal favorite of mine. The small town normally only houses about 800 residents, but during the summer thousands flock through to both visit and work seasonally. A must-do in this port is take the white pass scenic railway, which takes you up the top of mountains, following the journey of the men who built the railroad during the Klondike Gold Rush of the late 19th century. The ride is completely narrated by a guide so you can learn all about the history of the area while basking in the stunning views. Once you're back in town you should absolutely hit up Skagway brewing company for a spruce tip blonde ale & Klondike Doughboy for arguably the best fried dough you will have in your lifetime. If looking for fish, luckily both The Smokehouse & Skagway Fish Company are steps away from the cruise pier.
Ketchikan - Another favorite town port of tourists and probably the most bustling. If you are needing to bring souvenirs back to friends and family, this is the town to do it in. Head to Creek street and check out the charming little shops. Once upon time this was the city's red light district, but now the craziest thing you will probably see might be a bear trying to catch some salmon in the creek. Most ships stop in Ketchikan early in the morning, so I recommend you head to Alaska crepe co and pick up one of their famous breakfast crepes. The maple apple bacon? To die for. To no surprise, there is often a line up here - so I recommend putting your order in first thing. As far as excursions go, the Great Alaskan Lumberjack Show is a must. Feeling more adventurous? Hope on a fishing excursion (it is alaska's salmon capital after all) OR try out sea kayaking. You may even see some orcas here.

Sitka

Sitka is often interchangeable with Skagway. If you get both on your week long vacation - consider yourself lucky! Sitka, once apart of Russia, is a small town with a lot of character. Here history is as prevalent as the wildlife. Some of the top excursions include Totem Park, Raptor Center and Fortress of the Bear. You can also tack on a whale watching tour here if you were too busy hiking glaciers in Juneau!

Glacier Bay National Park

I cannot stress enough how gorgeous this place is. Unfortunately only a handful of ships have permits to this beautiful place, so when choosing a cruise - keep that in mind. Sitting on your balcony while sailing by icebergs and massive blue ice glaciers, listening to a naturalist, and sipping hot cocoa - is an experience everyone should have while we have the chance.

Day trips

It is popular amongst travelers to incorporate a land component to their cruise either before or after. Mostly in the Anchorage area. From here you can add Denali National Park and even Fairbanks. I recommend doing a Southbound tour starting with a few days in the Anchorage area, and then sailing down to Vancouver. If you do an inside passage tour, more often than not you will do a roundtrip out of Seattle. I advise giving yourself at least a full day in Seattle. Check out my guide on 24 hours in Seattle to see how to get the most out of your Alaskan vacation.

Juneau: Red Dog Saloon, Twisted Fish Company, Tracy's King Crab Shack.
Ketchikan: Alaska Crepe Co, Arctic Bar, 108 Taphouse & Burger Bar.
Skagway: Skagway Fish Co, The Smokehouse, The Station Bar & Grill
Sitka: Sitka's Burger & Crab Shack, SeaDaddy, Mean Queen
Icy Straight Point (Hoonah): The Cookhouse, The Fisherman's Daughter