Lockdown restrictions in Wales from 18th December

Alert level 1 Alert level 2 Alert level 3 Alert level 4
National lockdown All areas of Wales are currently in lockdown. This is equivalent to Alert level 4.
Face coverings Everyone must wear a face covering in indoor public settings, unless they have an exemption.
Support bubbles and extended households You may form a support bubble of up to three households (your own, plus two others). You may form a support bubble of up to two households (your own, plus one other). You may form an exclusive support bubble with a single person (for example, one multi-person household may join with a single one-person household).
Socialising Up to five people allowed indoors or in private outdoor settings (such as parks). Up to 30 people in public outdoor settings. Up to three people allowed in public indoor (such as cafés), public outdoor, or private outdoor settings. No socialising in private indoor settings. Up to three people allowed in public indoors and public outdoor areas. No socialising in private indoor or outdoor settings. Do not meet with people outside of your household or support bubble in any setting.
Working Everyone who is able to work from home should do so.
Public transport Walk or cycle if possible. Plan ahead to avoid busy times and routes.
Travel into Alert level area Allowed. Discouraged. Avoid travelling from a lower tier area into an Alert level 3 area. Extremely discouraged. People from lower tiers should not enter a Alert level 4 area without a valid reason.
Travel out of Alert level area Allowed. Discouraged. Avoid travelling out of the Alert level 3 area. If you do, continue to follow Alert level 3 rules. Avoid travelling outside of the UK. Extremely discouraged. Do not leave the area without reasonable excuse, and do not travel outside the UK.
Retail (essential and non-essential) Open. Essential retail, such as food stores and pharmacies, only.
Food and drink venues selling for consumption on premises (restaurants, pubs and bars) Open. May only serve alcohol between 6am and 10pm. Must close by 10:20pm. Open. May only serve alcohol between 6am and 10pm alongside a substantial meal. Must close by 10:20pm. Restaurants open but may not serve alcohol, and may only open for on premises dining between 6am and 6pm. Bars and pubs may only open for takeaway. Closed; except for takeaway.
Food and drink venues selling for consumption off premises (restaurants with delivery, click-and-collect, or drive-thru facilities) Open without restriction. Open. Alcohol may only be sold for takeaway. Off licenses must close by 10pm.
Personal care (hairdressers, barbers, beauty salons, tattoo parlours, tanning salons, and spas) Open. Closed.
Childcare services Open. Open for essential use only.
Outdoor public entertainment venues (theme parks, funfairs, zoos, botanical gardens, heritage sites) Open. Closed.
Indoor public entertainment venues (cinemas, theatres, museums, casinos, bowling alleys, bingo halls) Open. Open, with restricted visitor numbers. Closed.
Event halls and convention centres Open. Closed.
Nightclubs, discos, gentlemen's clubs Closed.
Accommodation services (hotels, hostels, campsites, B&Bs) Open. Closed.
Sport and leisure facilities (gyms, sports courts, leisure centres, swimming pools, golf courses and playgrounds) Open. Open, except for ice skating rinks. Closed.
Schools, colleges and universities Open. Students should attend as normal, unless they are self-isolating.
Libraries and community centres Open. Libraries open for click-and-collect services only. Community centres closed, except for essential public services.
Places of worship Open.
Weddings Allowed; attendance limit determined by venue. Wedding receptions up to 50 people indoors or 100 outdoors. Allowed; attendance limit determined by venue. Wedding receptions up to 15 people indoors or 30 outdoors. Allowed; attendance limit determined by venue. Wedding receptions forbidden.
Funerals Allowed; attendance limit determined by venue. Commemorative events (such as wakes) up to 50 people indoors or 100 outdoors. Allowed; attendance limit determined by venue. Commemorative events (such as wakes) up to 15 people indoors or 30 outdoors. Allowed; attendance limit determined by venue. Commemorative events (such as wakes) are forbidden.
Other services The following may remain open: crematoriums, playgrounds, public parks.

Disclaimer: This information is based on the published advice by each devolved government at the time that I look at it. It's not complete; it's not meant to be. There's a whole lot of exceptions and other random information that is impractical to display as a table—which is probably why they don't do it. Check your respective nation's official guidance if you think something seems off.